Remove remnants of building multi-release jars

Author: marcphilipp

gradle/plugins/common/src/main/kotlin/junitbuild.osgi-conventions.gradle.kts

@@ -48,10 +48,6 @@ tasks.withType<Jar>().named {
 				-fixupmessages.apiguardian.import: "Unused Import-Package instructions: \\[org.apiguardian.*\\]";is:=ignore
 				-fixupmessages.jspecify.import: "Unused Import-Package instructions: \\[org.jspecify.*\\]";is:=ignore
 
-				# This tells bnd to ignore classes it finds in `META-INF/versions/`
-				# because bnd doesn't yet support multi-release jars.
-				-fixupmessages.wrong.dir: "Classes found in the wrong directory: \\{META-INF/versions/...";is:=ignore
-
 				# Don't scan for Class.forName package imports.
 				# See https://bnd.bndtools.org/instructions/noclassforname.html
 				-noclassforname: true

junit-platform-console-standalone/junit-platform-console-standalone.gradle.kts

@@ -96,11 +96,6 @@ tasks {
 					// Pattern of key and value: `"Engine-Version-{YourTestEngine#getId()}": "47.11"`
 					"Engine-Version-junit-jupiter" to project.version,
 					"Engine-Version-junit-vintage" to project.version,
-					// Version-aware binaries are already included - set Multi-Release flag here.
-					// See https://openjdk.java.net/jeps/238 for details
-					// Note: the "jar --update ... --release X" command does not work with the
-					// shadowed JAR as it contains nested classes that do not comply with multi-release jars.
-					"Multi-Release" to true
 			))
 		}
 	}