[jdk21u-dev] RFR: 8325520: Vector loads and stores with indices and masks incorrectly compiled

[Martin Doerr]

Backport of [JDK-8325520](https://bugs.openjdk.org/browse/JDK-8325520). Required manual integration due to different context, but is recognized as clean. Included test has passed. Attention: There are related issues (see JBS).

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Commit messages:
 - Backport 0c934ff4e2fb53a72ad25a080d956745a5649f9b

Changes: https://git.openjdk.org/jdk21u-dev/pull/768/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=768&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325520
  Stats: 1465 lines in 5 files changed: 1463 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/768.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/768/head:pull/768

PR: https://git.openjdk.org/jdk21u-dev/pull/768