RFR: 8343317: Extend test generation tool to handle APX NDD/NF flavor of instructions

[hanklo6]

Extend test generation tool and gtest (added as part of https://bugs.openjdk.org/browse/JDK-8339507) to handle Intel APX NDD/NF instructions.

Intel Advanced Performance Extensions (APX) adds non destructive destination (NDD) and no flags (NF) flavor for the scalar instructions through EVEX encoding. For more information about APX, see https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html.

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Commit messages:
 - Add popcnt feature
 - Add ndd and nf tests

Changes: https://git.openjdk.org/jdk/pull/21795/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21795&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343317
  Stats: 3415 lines in 5 files changed: 2272 ins; 285 del; 858 mod
  Patch: https://git.openjdk.org/jdk/pull/21795.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21795/head:pull/21795

PR: https://git.openjdk.org/jdk/pull/21795