RFR: 8336356: [s390x] preserve Vector Register before using for string compress / expand [v2]

[Amit Kumar]

> This PR adds `TEMP` effect for the vector register, allotted by register allocator, used in the string compress/expand intrinsic. Also it enabled the Vector computation part of those intrinsics which was disabled by https://github.com/openjdk/jdk/pull/18162
> 
> tier1 test, which also includes string intrinsic tests `compiler/intrinsics/string/` are clean. No regression seen.

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  suggestion from Andrew

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22354/files
  - new: https://git.openjdk.org/jdk/pull/22354/files/a01706dd..3543e1c8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22354&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22354&range=00-01

  Stats: 23 lines in 2 files changed: 0 ins; 10 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/22354.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22354/head:pull/22354

PR: https://git.openjdk.org/jdk/pull/22354