[jdk21u-dev] RFR: 8343882: BasicAnnoTests doesn't handle multiple annotations at the same position

[SendaoYan]

Hi all,

This pull request contains a backport of commit [d562d3c7](https://github.com/openjdk/jdk/commit/d562d3c7a9e1e857c095ef908b0957b033972949) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Liam Miller-Cushon on 20 Dec 2024 and was reviewed by Joe Darcy.

Thanks!

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Commit messages:
 - Backport d562d3c7a9e1e857c095ef908b0957b033972949

Changes: https://git.openjdk.org/jdk21u-dev/pull/1276/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1276&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343882
  Stats: 18 lines in 1 file changed: 5 ins; 4 del; 9 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1276.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1276/head:pull/1276

PR: https://git.openjdk.org/jdk21u-dev/pull/1276