[libc++] Remove concurrency in the right libc++ job

Early-cancellation should have been removed from libcxx-run-benchmarks.yml
in the first place, not libcxx-build-and-test.yaml.

.github/workflows/libcxx-build-and-test.yaml

@@ -29,6 +29,10 @@ on:
 permissions:
   contents: read # Default everything to read-only
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
 jobs:
   stage1:
     if: github.repository_owner == 'llvm'

.github/workflows/libcxx-run-benchmarks.yml

@@ -23,10 +23,6 @@ env:
   CXX: clang++-22
   COMMENT_BODY: ${{ github.event.comment.body  }}
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
-  cancel-in-progress: true
-
 jobs:
   run-benchmarks:
     if: >-