Revert LLVM changes from #19007 (#19153)

See https://github.com/iree-org/iree/pull/19135 for a discussion.

Signed-off-by: Andrzej Warzynski <andrzej.warzynski@arm.com>
diff --git a/third_party/llvm-project b/third_party/llvm-project
index 889525f..2ab1021 160000
--- a/third_party/llvm-project
+++ b/third_party/llvm-project
@@ -1 +1 @@
-Subproject commit 889525fa99b251dc962edb516e0108088ba7e44d
+Subproject commit 2ab1021dcf1fd0443e6249ac848f6a0413d939bd