RFR JDK-8028321: Fix for String.split() empty input sequence/JDK-6559590 triggers regression.

[Xueming Shen]

Hi,

The change set for JDK-6559590 [1] triggers couple regression test failures in various areas.
It appears jdk8 source code itself has dependency on the "old" behavior of split() method
when the input sequence is an empty string (split-ing a zero-length input sequence always
returns the resulting array has just one element, the empty string itself). Given we are
at a very late stage of the release, seems like the best way to solve this issue for now is
to undo the change for 6559590. I will re-open 6559590 for future releases.

Here is the webrev for the undo. We still keep the change for 8027645

<http://cr.openjdk.java.net/%7Esherman/8027645/webrev/>http://cr.openjdk.java.net/~sherman/8028321/webrev/

Thanks!
-Sherman

[1] http://hg.openjdk.java.net/jdk8/tl/jdk/rev/9e37caf07ce0