Request for Review: Support build-infra output directory in langtools test

[Magnus Ihse Bursie]

There are several similarities between jdk/test/Makefile and 
langtools/test/Makefile. This makes it possible to run tests from either 
one in build-infra (the new build system) by using the target "test". In 
jdk/test/Makefile there is a test for an external variable 
ALT_OUTPUTDIR, which directs where the test results should be stored. 
The build-infra framework uses this to keep the test output in the 
corresponding build directory.

However, while the code is very similar in langtools/test/Makefile, this 
exact feature is not available. This results in langtools tests being 
hardcoded to end up in a directory named as in the old build system.

Here is a rather trivial patch that will add the ALT_OUTPUTDIR 
functionality to langtools as well.

http://cr.openjdk.java.net/~ihse/support-build-infra-output-in-langtools-test/webrev.00/

I'm assuming someone in the langtools group should review this as well, 
and that it probably should go in via the -tl forest. I couldn't figure 
out what mailing list to reach the langtools group on though, so I'd 
appreaciate some help with forwarding this to the right persons.

/Magnus