This is to facilitate the current experiment with class-level test
suite parallelism. It's our hope that with these changes, we can get
the runtime of the integration test suite down to 20 minutes or so.
-UnifiedGenotyper tests: these divided nicely into logical categories
that also happened to distribute the runtime fairly evenly
-UnifiedGenotyperPloidy: these had to be divided arbitrarily into two
classes in order to halve the runtime
-HaplotypeCaller: turns out that the tests for complex and symbolic
variants make up half the runtime here, so merely moving these into
a separate class was sufficient
-BiasedDownsampling: most of these tests use excessively large intervals
that likely can't be reduced without defeating the goals of the tests. I'm
disabling these tests for now until they can either be redesigned to use smaller
intervals around the variants of interest, or refactored into unit tests
(creating a JIRA for Yossi for this task)