[libunwind] [libunwind][AArch64] Disable ZA before resuming from unwinding (on Linux) (PR #165451)

[Benjamin Maxwell via cfe-commits]

================
@@ -827,6 +827,53 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
   ret
 #endif
 
+//
+// extern "C" bool __libunwind_Registers_arm64_za_disable()
+//
+// On return:
----------------
MacDue wrote:

Added some extra docs :+1: 

https://github.com/llvm/llvm-project/pull/165451