RFR : 8013528 : (XS) Provide SharedSecrets access to String(char[], boolean) constructor

[Mike Duigou]

Hello all;

This change originated as part of JDK-8006627 (which was also previously split into JDK-8007398 as well). It adds an internal mechanism for performance sensitive usages to create a string from a provided character array without copying that array. This saves both in the allocation (and subsequent GC) as well as the copying of the characters. There are a few places in the JDK that return Strings which can benefit from this change.

http://cr.openjdk.java.net/~mduigou/JDK-8013528/0/webrev/

Fear not, JDK-8006627 and JDK-8007398 will be revisited... For now it would be to get this change in to allow other potential users to move forward with their changes.

Mike