RFR: 8356152: String.concat can throw StringIndexOutOfBoundsException

[Raffaello Giulietti]

A fix to throw `OutOfMemoryError`, as done in releases ≤ 23.

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Commit messages:
 - 8356152: String.concat can throw StringIndexOutOfBoundsException

Changes: https://git.openjdk.org/jdk/pull/25038/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25038&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8356152
  Stats: 85 lines in 2 files changed: 84 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25038.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25038/head:pull/25038

PR: https://git.openjdk.org/jdk/pull/25038