RFR: 8062923: XSL: Run-time internal error in 'substring()'

[Aleksej Efimov]

Hi,

Please, review the fix for the XSL substring function failures. Two 
issues were reported during usage of this function:
1. Runtime internal error with negative length: 
https://bugs.openjdk.java.net/browse/JDK-8062923
2. Wrong answer when -Inf length is used: 
https://bugs.openjdk.java.net/browse/JDK-8062924

These two issues can be solved by fix proposed for the review: 
http://cr.openjdk.java.net/~aefimov/8062923/webrev.00

Testing:
xml related regression tests (with new test) - no failures (from jdk and 
jaxp repos).
JCK xml related tests - no failures.

With Best Regards,
Aleksej