JDK 9 RFR of 8030814: Long.parseUnsignedLong should throw exception on too large input

[Brian Burkhalter]

Issue:	https://bugs.openjdk.java.net/browse/JDK-8030814
webrev:	http://cr.openjdk.java.net/~bpb/8030814/webrev.2/

This review request follows from the discussion of last month in this thread:

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-December/024031.html

The contributed patch before my minor tweaking of it is here

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-December/024110.html

with a detailed explanation of its logic here

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-December/024136.html

I added to the java/lang/Long/Unsigned JTREG test the case from the issue report as well as some other cases which exercise both sides of the A v B overflow test.

Thanks,

Brian