Remove some TODOs from Java feature tests

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

tests/features1919/java19/RecordPatternsPreview1ExhaustivenessAspect.aj

     switch (pair) {
       case Pair<I>(I i, C c) -> System.out.println("x");
       case Pair<I>(I i, D d) -> System.out.println("y");
-      // TODO: Remove redundant default clause when https://github.com/eclipse-jdt/eclipse.jdt.core/issues/455 has been fixed.
       // Fixed since Java 21, see features1921/java21/RecordPatternsPreview1ExhaustivenessAspect.aj.
       default -> System.out.println("z");
     }
       case Pair<I>(C c, I i) -> System.out.println("a");
       case Pair<I>(D d, C c) -> System.out.println("b");
       case Pair<I>(D d1, D d2) -> System.out.println("c");
-      // TODO: remove redundant default clause when https://github.com/eclipse-jdt/eclipse.jdt.core/issues/455 has been fixed.
       // Fixed since Java 21, see features1921/java21/RecordPatternsPreview1ExhaustivenessAspect.aj.
       default -> System.out.println("d");
     }

tests/features1919/java19/RecordPatternsPreview1ExhaustivenessOK1.java

     switch (p2) {
       case Pair<I>(I i, C c) -> System.out.println("x");
       case Pair<I>(I i, D d) -> System.out.println("y");
-      // TODO: Remove redundant default clause when https://github.com/eclipse-jdt/eclipse.jdt.core/issues/455 has been fixed.
       // Fixed since Java 21, see features1921/java21/RecordPatternsPreview1ExhaustivenessOK1.java.
       default -> System.out.println("z");
     }
       case Pair<I>(C c, I i) -> System.out.println("a");
       case Pair<I>(D d, C c) -> System.out.println("b");
       case Pair<I>(D d1, D d2) -> System.out.println("c");
-      // TODO: Remove redundant default clause when https://github.com/eclipse-jdt/eclipse.jdt.core/issues/455 has been fixed.
       // Fixed since Java 21, see features1921/java21/RecordPatternsPreview1ExhaustivenessOK1.java.
       default -> System.out.println("d");
     }

tests/features1921/java21/StringPatternsPreview1.java

   public static void main(String[] args) {
     // Embedded expressions can be strings
     String firstName = "Bill", lastName = "Duck";
-    // TODO: Due to https://github.com/eclipse-jdt/eclipse.jdt.core/issues/1719, this is currently rendered incorrectly
     System.out.println(STR."\{firstName} \{lastName}");
 
     // Embedded expressions can perform arithmetic

tests/src/test/java/org/aspectj/systemtest/ajc1922/Java22PreviewFeaturesTests.java

     runTest("named aspect with simple main method");
   }
 
-  /**
-   * Still not implemented with the Java 21 release Eclipse 2023-12 (4.30),
-   * see <a href="https://github.com/eclipse-jdt/eclipse.jdt.core/issues/1106">GitHub issue 1106</a>.
-   */
   public void testUnnamedClassWithSimpleMainMethod() {
     runTest("unnamed class with simple main method");
   }

tests/src/test/resources/org/aspectj/systemtest/ajc1921/ajc1921.xml

 	<!-- Java 21 final, Java 17, 18, 19, 20 preview -->
 	<ajc-test dir="features1920/java20" vm="21" title="switch pattern matching preview 4 error">
 		<compile files="SwitchPatternPreview4Error.java" options="-21">
-			<!-- TODO: Add correct compiler error message, as soon as JDT Core supports it -->
 			<message kind="error" file="SwitchPatternPreview4Error.java" text="This case label is dominated by one of the preceding case labels"/>
 		</compile>
 	</ajc-test>
 	<!-- Java 21 final, Java 17, 18, 19, 20 preview -->
 	<ajc-test dir="features198/java17" vm="21" title="switch pattern matching error">
 		<compile files="SwitchPatternError.java" options="-21">
-			<!-- TODO: Add correct compiler error message, as soon as JDT Core supports it -->
 			<message kind="error" file="SwitchPatternError.java" text="This case label is dominated by one of the preceding case labels"/>
 		</compile>
 	</ajc-test>
 	<!-- Java 21 final, Java 17, 18, 19, 20 preview -->
 	<ajc-test dir="features1919/java19" vm="21" title="switch pattern matching preview 3 error 2">
 		<compile files="SwitchPatternPreview3Error2.java" options="-21">
-			<!-- TODO: Add correct compiler error message, as soon as JDT Core supports it -->
 			<message kind="error" file="SwitchPatternPreview3Error2.java" text="This case label is dominated by one of the preceding case labels"/>
 		</compile>
 	</ajc-test>
 	</ajc-test>
 
 	<!-- Java 21 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/893 is done -->
 	<ajc-test dir="features1921/java21" vm="21" title="unnamed patterns">
 		<compile files="UnnamedPatternsPreview1.java" options="--enable-preview -21"/>
 		<run class="UnnamedPatternsPreview1" vmargs="--enable-preview">
 	</ajc-test>
 
 	<!-- Java 21 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/893 is done -->
 	<ajc-test dir="features1921/java21" vm="21" title="unnamed patterns aspect">
 		<compile files="UnnamedPatternsPreview1Aspect.aj" options="--enable-preview -21"/>
 		<run class="UnnamedPatternsPreview1Aspect" vmargs="--enable-preview">
 	</ajc-test>
 
 	<!-- Java 21 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/1106 is done -->
 	<ajc-test dir="features1921/java21" vm="21" title="unnamed class with simple main method">
 		<compile files="UnnamedClassWithSimpleMainMethodPreview1.java" options="--enable-preview -21"/>
 		<run class="UnnamedClassWithSimpleMainMethodPreview1" vmargs="--enable-preview">

tests/src/test/resources/org/aspectj/systemtest/ajc1922/ajc1922.xml

 <suite>
 
 	<!-- Java 22 final, 21 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/893 is done -->
 	<ajc-test dir="features1921/java21" vm="22" title="unnamed patterns">
 		<compile files="UnnamedPatternsPreview1.java" options="-22"/>
 		<run class="UnnamedPatternsPreview1">
 	</ajc-test>
 
 	<!-- Java 22 final, 21 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/893 is done -->
 	<ajc-test dir="features1921/java21" vm="22" title="unnamed patterns aspect">
 		<compile files="UnnamedPatternsPreview1Aspect.aj" options="-22"/>
 		<run class="UnnamedPatternsPreview1Aspect">
 	</ajc-test>
 
 	<!-- Java 21, 22 preview -->
-	<!-- TODO: Activate after https://github.com/eclipse-jdt/eclipse.jdt.core/issues/1106 is done -->
 	<ajc-test dir="features1921/java21" vm="22" title="unnamed class with simple main method">
 		<compile files="UnnamedClassWithSimpleMainMethodPreview1.java" options="-22 --enable-preview"/>
 		<run class="UnnamedClassWithSimpleMainMethodPreview1" vmargs="--enable-preview">