Simplify usages of ProcessTools.createJavaProcessBuilder in our tests

There are a many places where arguments are converted and passed back and forth in String[] and Collections.

For example:
  ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
          argsList.toArray(new String[argsList.size()]));

If we add an overload the createJavaProcessBuilder, that takes a Collection<String> as an argument, then we can write the code above as:
   ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(argsList);

Other places temporarily put the flags in a String[], where most calls simply lists the arguments in the call:
  String[] opts = {Xmx, "-XX:NativeMemoryTracking=detail", "-XX:+UseParallelGC", "-version"};
  ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(opts);

And some places put the args in a temporary Collection:
  LinkedList<String> vmOptions = new LinkedList<>();
  vmOptions.add(gc);
  vmOptions.add("-Xmx" + minMaxHeap);
  vmOptions.add("-XX:+PrintFlagsFinal");
  vmOptions.add(VerifyHeapSize.class.getName());

  ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(vmOptions.toArray(new String[0]));

I'd like to cleanup, simplify, and unify many of these usages.