RFR: 7904079: Fix setting up length parameter for CXUnsavedFiles Struct [v6]

[Varada M]

> CXUnsavedFile struct contains three members, first two are pointers and last one is unsigned long. When jextract makes downcall to clang_reparseTranslationUnit_Impl it sets up the third parameter in the struct incorrectly. It sets INT instead of LONG so on big endian platform the parameter will be set differently. 
> 
> JBS Issue : [CODETOOLS-7904079](https://bugs.openjdk.org/browse/CODETOOLS-7904079)

Varada M has updated the pull request incrementally with one additional commit since the last revision:

  7904079: Fix setting up length parameter for CXUnsavedFiles Struct

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Changes:
  - all: https://git.openjdk.org/jextract/pull/289/files
  - new: https://git.openjdk.org/jextract/pull/289/files/6043e0dd..550b0303

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jextract&pr=289&range=05
 - incr: https://webrevs.openjdk.org/?repo=jextract&pr=289&range=04-05

  Stats: 80 lines in 1 file changed: 79 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jextract/pull/289.diff
  Fetch: git fetch https://git.openjdk.org/jextract.git pull/289/head:pull/289

PR: https://git.openjdk.org/jextract/pull/289