Use '-Djava.security.manager=allow' on Java 18+ (JEP 411)

JEP 411: Deprecate the Security Manager for Removal,
see https://openjdk.java.net/jeps/411.

As of Java 18, the new API for blocking System.exit is not available
yet, see https://bugs.openjdk.java.net/browse/JDK-8199704.

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

pom.xml

 				<jvm.arg.addOpens>--add-opens java.base/java.lang=ALL-UNNAMED</jvm.arg.addOpens>
 			</properties>
 		</profile>
+		<profile>
+			<id>jdk-18-to-xx</id>
+			<activation>
+				<jdk>[18,)</jdk>
+			</activation>
+			<properties>
+				<!--
+					JEP 411: Deprecate the Security Manager for Removal, see https://openjdk.java.net/jeps/411.
+					As of Java 18, the new API for blocking System.exit is not available yet, see
+					https://bugs.openjdk.java.net/browse/JDK-8199704.
+				-->
+				<jvm.arg.addOpens>-Djava.security.manager=allow</jvm.arg.addOpens>
+			</properties>
+		</profile>
 		<profile>
 			<id>release</id>
 			<properties>

testing/src/test/java/org/aspectj/testing/harness/bridge/JavaRun.java

 	public static class Spec extends AbstractRunSpec {
 		static {
 			try {
+				// TODO: Deprecate the Security Manager for Removal, see https://openjdk.java.net/jeps/411.
+				//       As of Java 18, the new API for blocking System.exit is not available yet, see
+				//       https://bugs.openjdk.java.net/browse/JDK-8199704.
 				System.setSecurityManager(RunSecurityManager.ME);
 			} catch (Throwable t) {
 				System.err.println("JavaRun: Security manager set - no System.exit() protection");