Add GHA UPB macOS bazel coverage for Apple Silicon

This is based on cl/525134469 which sets up coverage for C++

PiperOrigin-RevId: 542600526
diff --git a/.github/workflows/bazel_tests.yml b/.github/workflows/bazel_tests.yml
index 76cdf27..a90b3f5 100644
--- a/.github/workflows/bazel_tests.yml
+++ b/.github/workflows/bazel_tests.yml
@@ -21,14 +21,16 @@
       matrix:
         include:
           - { NAME: "Fastbuild", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "" }
-          - { NAME: "Optmized", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "-c opt" }  # Some warnings only fire with -c opt
+          - { NAME: "Optimized", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "-c opt" }  # Some warnings only fire with -c opt
           - { NAME: "GCC Optimized", BAZEL: bazel, CC: gcc-12, os: ubuntu-22.04, flags: "-c opt" }
           - { NAME: "FastTable", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "--//:fasttable_enabled=true -- -cmake:test_generated_files" }
           - { NAME: "ASAN", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "--config=asan -c dbg -- -benchmarks:benchmark -python/..." }
           - { NAME: "UBSAN", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "--config=ubsan -c dbg -- -benchmarks:benchmark -python/... -lua/...", install: "libunwind-dev" }
           - { NAME: "32-bit", BAZEL: bazel, CC: clang, os: ubuntu-20-large, flags: "--copt=-m32 --linkopt=-m32 -- -... benchmarks:benchmark ", install: "g++-multilib" }
-          - { NAME: "macOS", BAZEL: bazel, CC: clang, os: macos-11 }
           - { NAME: "Windows", BAZEL: bazel, os: windows-2019, startup-flags: "--output_user_root=C:/tmp", flags: "--config=cpp17_msvc", targets: "upb/... upbc/... python/... protos/... protos_generator/..." }
+          - { NAME: "macOS", BAZEL: bazel, CC: clang, os: macos-11 }
+          # Current github runners are all Intel based, so just build/compile for Apple Silicon to detect issues there.
+          - { NAME: "macOS ARM (build only)", BAZEL: bazel, BAZEL_CMD: build, CC: clang, os: macos-11, flags: "--cpu=darwin_arm64"}
           # We support two Bazel versions back per https://opensource.google/documentation/policies/cplusplus-support
           - { NAME: "Bazel 4.1.0", BAZEL: bazel-4.1.0-linux-x86_64, CC: clang, os: ubuntu-20-large }
           - { NAME: "Bazel 5.3.0", BAZEL: bazel-5.3.0-linux-x86_64, CC: clang, os: ubuntu-20-large }
@@ -72,7 +74,7 @@
         if: matrix.CC
         run: echo "CC=${{ matrix.CC }}" >> $GITHUB_ENV
       - name: Run tests
-        run: cd ${{ github.workspace }} && ${{ matrix.BAZEL }} ${{ matrix.startup-flags }} test --test_output=errors ${{ steps.bazel-cache.outputs.cache_args }} ${{ matrix.targets || '...' }} ${{ matrix.flags }}
+        run: cd ${{ github.workspace }} && ${{ matrix.BAZEL }} ${{ matrix.startup-flags }} ${{ matrix.BAZEL_CMD || 'test' }} --test_output=errors ${{ steps.bazel-cache.outputs.cache_args }} ${{ matrix.targets || '...' }} ${{ matrix.flags }}
 
   no-python:
     runs-on: ubuntu-20-large