zlib: Preserve executable bit from extracted archives on POSIX systems.

If a file is readable for U/G/O when created, and the archive entry has
an extended file attribute indicating that it is executable for that
category, the file will be marked as executable for that category.

Fixed: 555011
Change-Id: I79bed3525eada71f34cde38d684e9708fc138113
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3379289


Reviewed-by: François Degros <fdegros@chromium.org>
Auto-Submit: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Joshua Pawlicki <waffles@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958103}
NOKEYCHECK=True
GitOrigin-RevId: 35e7398d2d51b23faeb4e8459f8419af99733b44