JDK 9 RFR of JDK-8169903: Refactor spliterator traversing tests into a library

[Amy Lu]

java/util/Spliterator/SpliteratorTraversingAndSplittingTest.java
java/util/Spliterator/SpliteratorCollisions.java

Test functions in above tests are almost duplicate with functions in 
java/util/stream/SpliteratorTestHelper.java. Test can reuse test 
functions from SpliteratorTestHelper, but with it’s own DataProvider.

Please review the patch for refactoring spliterator traversing tests.

bug: https://bugs.openjdk.java.net/browse/JDK-8169903
webrev: http://cr.openjdk.java.net/~amlu/8169903/webrev.00/

SpliteratorTestHelper.java has a minor update, added one small testcase 
that originally from SpliteratorCollisions.testForEach.

The two skipped tests in SpliteratorCollisions.java are now enabled 
back, as mentioned bug has already been fixed.
256 /* skip this test until 8013649 is fixed
...
268 */

This patch also brings back Integer.MAX_VALUE test data which requires 
big memory (and removed in JDK-8169838), in a separate test.

Thanks,
Amy