unblock CI concurrency.

The original rules were copied from LLVM.  However
these rules are too restrictive in practice when
lots of PRs are in flight.

.github/workflows/amd-aie-tests.yml

@@ -13,9 +13,11 @@ on:
       - 'aie-public'
 
 concurrency:
-  # Skip intermediate builds: always.
+  # A PR number if a pull request and otherwise the commit hash. This cancels
+  # queued and in-progress runs for the same PR (presubmit) or commit
+  # (postsubmit).
   # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
+  group: ${{ github.workflow }}-${{ github.event.number || github.sha }}
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs:

.github/workflows/amd-upstream-tests.yml

@@ -13,9 +13,11 @@ on:
       - 'aie-public'
 
 concurrency:
-  # Skip intermediate builds: always.
+  # A PR number if a pull request and otherwise the commit hash. This cancels
+  # queued and in-progress runs for the same PR (presubmit) or commit
+  # (postsubmit).
   # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
+  group: ${{ github.workflow }}-${{ github.event.number || github.sha }}
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs: