[jdk21u-dev] RFR: 8323577: C2 SuperWord: remove AlignVector restrictions on IR tests added in JDK-8305055

[Andrew Lu]

I backport this for parity with 21.0.5-oracle.

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Commit messages:
 - Backport 45c65e6b1ac06aa06757393f1752661252e6f827

Changes: https://git.openjdk.org/jdk21u-dev/pull/628/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=628&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323577
  Stats: 13 lines in 2 files changed: 0 ins; 12 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/628.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/628/head:pull/628

PR: https://git.openjdk.org/jdk21u-dev/pull/628