Merge topic 'xcode-pch' into release-3.23

476c6a8910 PCH: Fix Xcode non-pch language exclusion
fcf1fcfd0c Tests: Ignore all classes in Xcode internal objc warnings

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !7166