RFR: 8271515: Integration of JEP 417: Vector API (Third Incubator)

[Paul Sandoz]

This PR improves the performance of vector operations that accept masks on architectures that support masking in hardware, specifically Intel AVX512 and ARM SVE.

On architectures that do not support masking in hardware the same technique as before is applied to most operations, specifically composition using blend.

Masked loads/stores are a special form of masked operation that require additional care to ensure out-of-bounds access throw exceptions. The range checking has not been fully optimized and will require further work.

No API enhancements were required and only a few additional tests were needed.

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

Commit messages:
 - Apply patch from https://github.com/openjdk/panama-vector/pull/142
 - Apply patch from https://github.com/openjdk/panama-vector/pull/139
 - Apply patch from https://github.com/openjdk/panama-vector/pull/151
 - Add new files.
 - 8271515: Integration of JEP 417: Vector API (Third Incubator)

Changes: https://git.openjdk.java.net/jdk/pull/5873/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5873&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271515
  Stats: 21999 lines in 106 files changed: 16228 ins; 2077 del; 3694 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5873.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5873/head:pull/5873

PR: https://git.openjdk.java.net/jdk/pull/5873