RFR: 8318678: Vector access on heap MemorySegments only works for byte[]

[Per Minborg]

This PR proposes removing the restriction that only heap `MemorySegment` wrapping a `byte` array can be accessed by Vectors. Now any array type can be used provided the element alignment constraints are respected.

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Commit messages:
 - Vector access on heap MemorySegments for all array types

Changes: https://git.openjdk.org/jdk/pull/16360/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16360&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318678
  Stats: 269 lines in 41 files changed: 126 ins; 23 del; 120 mod
  Patch: https://git.openjdk.org/jdk/pull/16360.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16360/head:pull/16360

PR: https://git.openjdk.org/jdk/pull/16360