[3.12] gh-110190: Fix ctypes structs with array on PPCLE64 (GH-112959) (#113170)

Fix the same issue of PR #112604 on PPC64LE platform
Refactor tests to make easier to add more platfroms if needed.

(cherry picked from commit 6644ca45cde9ca1b80513a90dacccfeea2d98620)
Change-Id: I31730a3ebe558570ce1d7a3b26db8392f18d1770