Integrate LLVM to llvm/llvm-project@831ed97b1215 (#24603)

Carries the FuncToEmitC Bazel-deps fix (add :IR and //llvm:Support),
needed by upstream 123078c21cfb.

Signed-off-by: Roberto Laudani <laudani@roofline.ai>

third_party/llvm-project

diff --git a/third_party/llvm-project b/third_party/llvm-project
index 696f4d5..a7d5cac 160000
--- a/third_party/llvm-project
+++ b/third_party/llvm-project
@@ -1 +1 @@
-Subproject commit 696f4d5628479a828a14aa9999974d48f0aa698f
+Subproject commit a7d5cacef56e767f154509f8f9a47e933614704f