Bump JDT Core from 1.9.7.M2 to 1.9.8-SNAPSHOT

Not Java 17 compatible yet, but refreshed from main branch for latest
Java 16 updates in compiler (mostly about records).

Let's see if CI is still green before trying to upgrade JDT Core to
Java 17 beta.

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

pom.xml

@@ -21,7 +21,8 @@
 		<maven.javadoc.skip>true</maven.javadoc.skip>
 
 		<!-- Dependency versions -->
-		<jdt.core.version>1.9.7.M2</jdt.core.version>
+<!--		<jdt.core.version>1.9.7.M2</jdt.core.version>-->
+		<jdt.core.version>1.9.8-SNAPSHOT</jdt.core.version>
 		<asm.version>9.2</asm.version>
 		<lib.ant.version>1.6.3</lib.ant.version>
 		<lib.ant.xerces.version>2.6.2</lib.ant.xerces.version>