RFR: 8255150: Add utility methods to check long indexes and ranges [v3]

[Roland Westrelin]

> This change add 3 new methods in Objects:
> 
> public static long checkIndex(long index, long length)
> public static long checkFromToIndex(long fromIndex, long toIndex, long length)
> public static long checkFromIndexSize(long fromIndex, long size, long length)
> 
> This mirrors the int utility methods that were added by JDK-8135248
> with the same motivations.
> 
> As is the case with the int checkIndex(), the long checkIndex() method
> is JIT compiled as an intrinsic. It allows the JIT to compile
> checkIndex to an unsigned comparison and properly recognize it as
> a range check that then becomes a candidate for the existing range check
> optimizations. This has proven to be important for panama's
> MemorySegment API and a prototype of this change (with some extra c2
> improvements) showed that panama micro benchmark results improve
> significantly.
> 
> This change includes:
> 
> - the API change
> - the C2 intrinsic
> - tests for the API and the C2 intrinsic
> 
> This is a joint work with Paul who reviewed and reworked the API change
> and filled the CSR.

Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:

  intrinsic comments

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1003/files
  - new: https://git.openjdk.java.net/jdk/pull/1003/files/b47184ac..aaacd328

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1003&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1003&range=01-02

  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1003.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1003/head:pull/1003

PR: https://git.openjdk.java.net/jdk/pull/1003