RFR: 7903984: Inline upcallHandle method to reduce shared code across multiple generations [v2]

[Nizar Benalla]

> Please review this patch to inline the upcallHandle method, reducing the amount of shared items across multiple jextract generations.
> 
> Edit: all tests pass in CI, GitHub failure is unrelated 
> 
> TIA

Nizar Benalla has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge branch 'master' into inline-upcallhandle
   
   # Conflicts:
   #	src/main/java/org/openjdk/jextract/impl/HeaderFileBuilder.java
 - remove whitespace
 - inline method

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Changes: https://git.openjdk.org/jextract/pull/279/files
  Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=279&range=01
  Stats: 18 lines in 2 files changed: 8 ins; 8 del; 2 mod
  Patch: https://git.openjdk.org/jextract/pull/279.diff
  Fetch: git fetch https://git.openjdk.org/jextract.git pull/279/head:pull/279

PR: https://git.openjdk.org/jextract/pull/279