RFR: 8364936: Shenandoah: Switch nmethod entry barriers to conc_instruction_and_data_patch

[Cesar Soares Lucas]

Hi all,

This pull request contains a backport of commit [81a1e8e1](https://github.com/openjdk/jdk/commit/81a1e8e1363446de499a59fc706221efde12dd86) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Cesar Soares Lucas on 8 Sep 2025 and was reviewed by Fei Yang, Dingli Zhang, Kelvin Nilsen and William Kemper.

I had to manually resolve a merge conflict in `TestHotSpotVMConfig.java` because the original patch modified a region of the file that is not present in this repository version of the same file.

Thanks!

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Commit messages:
 - Revert some changes due to non-ZGC using the old patching type.
 - Backport 81a1e8e1363446de499a59fc706221efde12dd86

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/218/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=218&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364936
  Stats: 21 lines in 9 files changed: 0 ins; 15 del; 6 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/218.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/218/head:pull/218

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/218