Review Request JDK-8136930 Examine implications for custom launchers, equivalent of java -X options in particular

[Mandy Chung]

Harold has incorporated feedback from David, Coleen, Lois and others and updated webrev:
   http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8136930/webrev.02/

The only change compared to webrev.01 is in hotspot arguments.{cpp,hpp} and a new ModuleOptionsTest.java.

I see concerns from Coleen on the option name and syntax.  I’d like to separate that discussion from this fix and follow up after this push unless any objection.

Mandy