RFR: 8351462: Improve robustness of String concatenation [v2]

[Raffaello Giulietti]

> Early detection of an `int` overflow in `StringConcatHelper` improves robustness of `StringConcatFactory`.

Raffaello Giulietti has updated the pull request incrementally with one additional commit since the last revision:

  Bumped copyright year.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24546/files
  - new: https://git.openjdk.org/jdk/pull/24546/files/b491a1d8..ed313ded

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24546&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24546&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24546.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24546/head:pull/24546

PR: https://git.openjdk.org/jdk/pull/24546