Revert "[msan] Add avx512-intrinsics.ll and avx512-intrinsics-upgrade.ll test case (#123980)"

This reverts commit 980e86f.

Reason: buildbot breakage
(https://lab.llvm.org/buildbot/#/builders/154/builds/10901/steps/5/logs/FAIL__LLVM__avx512-intrinsics-upgrade_ll)

Author: thurstond