RFR: 8365765: thread.inline.hpp includes the wrong primary header file

[Paul Hübner]

Hi all,

This ensures `thread.inline.hpp` adheres to the style guide:
> All .inline.hpp files should include their corresponding .hpp file as the first include line with a blank line separating it from the rest of the include lines. [...]

I've run tests with JDK tiers 1-3 on macOS (AArch64, x64), Linux (AArch64, x64), and Windows (x64); all green.

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Commit messages:
 - Fix primary header for thread.inline.hpp.

Changes: https://git.openjdk.org/jdk/pull/26896/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26896&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365765
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26896.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26896/head:pull/26896

PR: https://git.openjdk.org/jdk/pull/26896