squash! Run StandaloneTests for Java 8 under Java 8

To make tests executeOnJava8() and executeOnJava8SelectPackage() see the
class files, update test compile() to use option `--release 8`.  Because
compiling to release 8 is deprecated, add a linter option to disable the
warning to make compile() pass.

Author: rybak

platform-tooling-support-tests/src/test/java/platform/tooling/support/tests/StandaloneTests.java

@@ -89,6 +89,8 @@ void compile() throws Exception {
 		var result = Request.builder() //
 				.setTool(new Javac()) //
 				.setProject("standalone") //
+				.addArguments("-Xlint:-options")
+				.addArguments("--release", "8")
 				.addArguments("-proc:none") //
 				.addArguments("-d", workspace.resolve("bin")) //
 				.addArguments("--class-path", MavenRepo.jar("junit-platform-console-standalone")) //