RFR: 8332442: C2: refactor Mod cases in Compile::final_graph_reshaping_main_switch()

[Kangcheng Xu]

Hello all. This patch addresses [JDK-8332442](https://bugs.openjdk.org/browse/JDK-8332442) and refactors `Op_ModI`/`Op_ModL`/`Op_UModI`/`Op_UModL` cases in `DIVMOD` transforamtions. The purpose of the transformation to convert adjacent div `/`  and mod `%` operations of the same operands into one should the platform support this feature (e.g., x86-64).

I took the liberty adding _signed_ DIVMOD nodes (i.e., `DIV_MOD_I` and `DIV_MOD_L`) to the `IRNode` class constants as they are previously missing. Please let me know if they were left intentionally and if there are any other concerns. Thanks!

~This will be a draft PR before GHA tests are confirmed passing.~

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Commit messages:
 - Merge branch 'master' into refactor-mod-cases
 - Add test and IRNode for signed int/long divmod
 - created IR tests
 - passing tier1 tests
 - refactor divmod ops to handle_div_mod_op

Changes: https://git.openjdk.org/jdk/pull/20877/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20877&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332442
  Stats: 262 lines in 6 files changed: 194 ins; 64 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/20877.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20877/head:pull/20877

PR: https://git.openjdk.org/jdk/pull/20877