RFR: 7904079: Fix setting up length parameter for CXUnsavedFiles Struct

[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)

-------------

Commit messages:
 - CODETOOLS-7904079: Fix setting up length parameter for CXUnsavedFiles Struct

Changes: https://git.openjdk.org/jextract/pull/289/files
  Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=289&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904079
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 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