Integrate LLVM at llvm/llvm-project@21fd87595297

Updates LLVM usage to match
[21fd87595297](https://github.com/llvm/llvm-project/commit/21fd87595297)

PiperOrigin-RevId: 383591351
Change-Id: Iaa181fed4e6a89d9b73f6fbd351e66e8ee63ce4e
diff --git a/third_party/llvm/workspace.bzl b/third_party/llvm/workspace.bzl
index 4ce56ff..73bfc49 100644
--- a/third_party/llvm/workspace.bzl
+++ b/third_party/llvm/workspace.bzl
@@ -4,8 +4,8 @@
 
 def repo(name):
     """Imports LLVM."""
-    LLVM_COMMIT = "d38b9f1f31b1fa8ee885cfcd4ee7bd69771088c8"
-    LLVM_SHA256 = "4dac2be3c82bedd137b60b77ffb36ac203c2a2209278d589db6326e6a8fee499"
+    LLVM_COMMIT = "21fd8759529707b0f4430ebe8f27a01edc7f655e"
+    LLVM_SHA256 = "f71c858ea9e4584be0d0b46de18ec2238b810a060ce4a41cc9da6ffb9f96aa0b"
 
     tf_http_archive(
         name = name,