Add jvm args option. I rather not hardcode some large value just for...

Add jvm args option.  I rather not hardcode some large value just for Volantis.  This can easily be passed in from sign-build.sh and should be a no-op for any other tools

Bug: 17393134
Change-Id: Ic2325d7c1e1e7292c9339e169efbed526f82263c