testing jigsaw builds

[Mark Reinhold]

> Date: Mon, 15 Mar 2010 16:55:14 -0700
> From: jonathan.gibbons at sun.com

> getSystemJavaCompiler() will only look in tools.jar if the classes are not
> already available in the existing classloader.  If you're running a jdk module
> image, does that not have the javac classes available?

Yes, if the the module containing javax.tools.ToolProvider (i.e.,
sun.langtools) is declared to have an optional dependence upon the
javac module, and the javac module is installed.

- Mark