JDK 9 RFR of JDK-8035076: Pattern$BnMS never used due to bug in Pattern$BnM.optimize

[Xueming Shen]

Hi,

Please help codereview the change for JDK-8035076.

Issue:    https://bugs.openjdk.java.net/browse/JDK-8035076
Webrev: http://cr.openjdk.java.net/~sherman/8035067/webrev

This is regression caused by the change we made back to jdk7 to support case
insensitive match, in which a base class SliceNode for Slice family was 
added and
we mistakenly subclass the SliceS class to this newly added class, 
instead of
the original Slice class. The BnM optimization for supplementary 
support, which
is based on the "instanceof Slice", is therefor disabled. Below is the 
original
webrev for that changeset.

http://cr.openjdk.java.net/~sherman/6486934_6233084_6504326_6436458

The proposed change is to subclass SliceS from Slice node. The change 
has been
verified via the test case attached in the issue report. However I 
decided not to
include this test as a regression test as it is too "implementation 
detail dependent".

Thanks!
-Sherman