[clang] [clang] Avoid memcopy for small structure with padding under -ftrivial-auto-var-init (PR #71677)

[Omair Javaid via cfe-commits]

omjavaid wrote:

This change appears to have broken several clang tests on following buildbots:
https://lab.llvm.org/buildbot/#/builders/245
https://lab.llvm.org/buildbot/#/builders/188
https://lab.llvm.org/buildbot/#/builders/186
https://lab.llvm.org/buildbot/#/builders/183

Kindly fix issues if they look trivial or revert the patch if more time is needed for the fix.

https://github.com/llvm/llvm-project/pull/71677