[llvm] [Github] Add initial version of precommit checks (PR #80951)

[Aiden Grossman via llvm-commits]

================
@@ -0,0 +1,47 @@
+name: "Precommit tests"
+
+permissions:
+  contents: read
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - '.github/workflows/precommit.yaml'
+      - 'llvm/**'
+
----------------
boomanaiden154 wrote:

Good point. It currently just keeps running multiple jobs and won't cancel the out of date ones. I've added the default concurrency group associated with the PR to fix this.

https://github.com/llvm/llvm-project/pull/80951