tools: run macOS test workflow with Xcode 16.1

We have to remove `macos-13` as it doesn't have Xcode 16 available.

Refs: #56824
PR-URL: #56831
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>

.github/workflows/test-macos.yml

@@ -30,6 +30,7 @@ concurrency:
 
 env:
   PYTHON_VERSION: '3.12'
+  XCODE_VERSION: '16.1'
   FLAKY_TESTS: keep_retrying
 
 permissions:
@@ -40,9 +41,7 @@ jobs:
     if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
-      matrix:
-        macos-version: [macos-13, macos-14]
-    runs-on: ${{ matrix.macos-version }}
+    runs-on: macos-14
     env:
       CC: sccache gcc
       CXX: sccache g++
@@ -56,6 +55,8 @@ jobs:
         uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b  # v5.3.0
         with:
           python-version: ${{ env.PYTHON_VERSION }}
+      - name: Set up Xcode ${{ env.XCODE_VERSION }}
+        run: sudo xcode-select -s /Applications/Xcode_${{ env.XCODE_VERSION }}.app
       - name: Set up sccache
         uses: mozilla-actions/sccache-action@054db53350805f83040bf3e6e9b8cf5a139aa7c9  # v0.0.7
         with: