RFR: 8349624: Validation for slot missing in CodeBuilder local variable instructions

[Chen Liang]

In CodeBuilder, validation for a slot was missing due to concurrent patches, and the original patch did not add effective tests for CodeBuilder because of the complex exceptional behaviors. Now the bug is fixed with renames to prevent future risky usages, and the tests have been enhanced to ensure at least the failure-case behavior (while the non-failure case is harder to check due to exceptional behaviors)

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Commit messages:
 - 8349624: Validation for slot missing in CodeBuilder local variable instructions

Changes: https://git.openjdk.org/jdk/pull/23522/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23522&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349624
  Stats: 61 lines in 2 files changed: 38 ins; 1 del; 22 mod
  Patch: https://git.openjdk.org/jdk/pull/23522.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23522/head:pull/23522

PR: https://git.openjdk.org/jdk/pull/23522