RFR: 8355276: Sort C2 includes

[Manuel Hässig]

This PR sorts the includes in `hotspot/share/opto` using `test/hotspot/jtreg/sources/SortIncludes.java` and enforces sorted includes for C2 sources in `sources/TestIncludesAreSorted.java`.

Testing:
 - [ ] [Github Actions](https://github.com/mhaessig/jdk/actions/runs/15773777177)
 - [ ] tier1,tier2 plus Oracle internal testing on Oracle supported platforms

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Commit messages:
 - Enforce sorted includes in hotspot/share/opto
 - Sort includes in C2 sources

Changes: https://git.openjdk.org/jdk/pull/25910/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25910&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355276
  Stats: 119 lines in 40 files changed: 57 ins; 55 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/25910.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25910/head:pull/25910

PR: https://git.openjdk.org/jdk/pull/25910