RFR: 8365047: Remove exception handler stub code in C2

[Ruben]

The C2 exception handler stub code is only a trampoline to the generated exception handler blob. This change removes the extra step on the way to the generated blob.

According to some comments in the source code, the exception handler stub code used to be patched upon deoptimization, however presumably these comments are outdated as the patching upon deoptimization happens for post-call NOPs only.

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Commit messages:
 - 8365047: Remove exception handler stub code in C2

Changes: https://git.openjdk.org/jdk/pull/26678/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26678&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365047
  Stats: 204 lines in 16 files changed: 19 ins; 180 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/26678.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26678/head:pull/26678

PR: https://git.openjdk.org/jdk/pull/26678