[TESTBUG] Profile based regression test groups for jdk repo

To run regression tests on compact profiles we need to identify which tests are capable of running on which profile.

This change introduces the TEST.groups file to allow jtreg to run regression tests by groups - where the groups are defined to support testing of compact profiles and the minimal VM.

The primary groups are:
 - jdk
 - jre
 - compact3
 - compact2
 - compact2_minimal
 - compact1
 - compact1_minimal

The minimal VM is only supported on compact1 and compact2.

To select a group of tests you use :<group-name>

Eg to run only those tests that can run on compact1 use:

jtreg :compact1

Of course you still need to point jtreg at the right kind of runtime image (and give it a full JDK as the compile-jdk!); and if testing the minimal VM you need to tell jtreg to select it using -javaoptions:-minimal

The full jtreg group facility is only available in the most recent jtreg builds, so you will need to grab the latest nightly build, or latest sources.

Note: once this is in place, anyone writing regression tests will need to be aware of whether that test is limited to certain profiles and update the group file accordingly. Sometimes it is not the item being tested that determines the minimum needed profile, but the test infrastructure eg if it uses XML.

See TEST.groups for more information.

The initial group definitions proposed here are not complete. There are over 4000 tests of the "desktop" that can not be readily executed manually and it may be that a number of these tests will require a JDK rather than the full JRE. Our full test processes will discover this and update the lists as needed.