Add jdk.incubator.vector during benchmark testing. (#138167)

This commit add jdk.incubator.vector during benchmark testing.

A number of the benchmarking tests now assert implementations of bench scenarios that leverage the Panama Vector API, so just like in other places we can add the vector module during test.

Author: ChrisHegarty

benchmarks/build.gradle

@@ -91,6 +91,12 @@ tasks.named("run").configure {
   systemProperty 'es.nativelibs.path', TestUtil.getTestLibraryPath(file("../libs/native/libraries/build/platform/").toString())
 }
 
+tasks.named('test').configure {
+  if (buildParams.getRuntimeJavaVersion().map{ it.majorVersion.toInteger() }.get() >= 21) {
+    jvmArgs '--add-modules=jdk.incubator.vector'
+  }
+}
+
 spotless {
   java {
     // IDEs can sometimes run annotation processors that leave files in