JDK 9 RFR of JDK-8174171: Move spliterator testing of BitSet into big memory tests BitSetStreamTest

[Amy Lu]

Please review this test-only change.

Integer.MAX_VALUE bit set testdata in bitStreamTestcases of 
SpliteratorTraversingAndSplittingTest was removed in JDK-8169838 due to 
out of memory errors. It also cause issue in BitSetStreamTest 
(JDK-8079538). And yes, testing for this do consume lots of memory.

This patch moved the spliterator testing of BitSet into big memory tests 
BitSetStreamTest:

1) bitStreamTestcases removed from SpliteratorTraversingAndSplittingTest
2) Above test cases, with adding back Integer.MAX_VALUE testdata, now is 
in the newly introduced @DataProvider and being tested in BitSetStreamTest.
3) It's better BitSetStreamTest not to be run concurrently with other 
test so to avoid memory usage conflict. With this purpose,
BitSetStreamTest moved to java/util/BitSet/stream subdir, and this 
subdir added to exclusiveAccess.dirs

bug: https://bugs.openjdk.java.net/browse/JDK-8174171
webrev: http://cr.openjdk.java.net/~amlu/8174171/webrev.00/

Thanks,
Amy