Fix CI (#776)

This PR updates to aspects of the CI to fix blocked PRs:

It moves the Bazel CI into its own set of actions, so failure can be isolated from other tasks.
Updates the clang-cl version used in CI for self-vendored build as it was failing with the default.

.github/workflows/main.yml

@@ -107,6 +107,19 @@ jobs:
         mkdir libs
         cp libsnmallocshim*.so libs
         for lib in `ls libs`; do echo; echo Testing $lib; ninja clean; LD_PRELOAD=libs/$lib ninja libsnmallocshim.so; done
+
+  bazel:
+    strategy:
+      matrix:
+        # Build each combination of OS and release/debug variants
+        os: [ "ubuntu-24.04", "ubuntu-22.04", "macos-13", "macos-14", "macos-15"  ]
+        build-type: [ "Release", "Debug" ]
+      # Don't abort runners if a single one fails
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    name: Bazel - ${{ matrix.os }} ${{ matrix.build-type }}
+    steps:
+    - uses: actions/checkout@v4
     - uses: bazelbuild/setup-bazelisk@v3
     - name: Mount bazel cache  # Optional
       uses: actions/cache@v4
@@ -115,6 +128,8 @@ jobs:
         key: bazel
     - run: bazel build -c opt //:snmalloc
     - run: bazel build -c opt //:snmalloc-rs
+    - run: bazel test -c opt --config=asan //fuzzing:snmalloc_fuzzer
+      if: ${{ matrix.os != 'macos-13' && matrix.os != 'macos-14' && matrix.os != 'macos-15' }}
 
   # If this looks remarkably familiar, that's because it is.  Sigh.
   macos:
@@ -159,15 +174,6 @@ jobs:
         mkdir libs
         cp libsnmallocshim*.so libs
         for lib in `ls libs`; do echo; echo Testing $lib; ninja clean; LD_PRELOAD=libs/$lib ninja libsnmallocshim.so; done
-    - uses: bazelbuild/setup-bazelisk@v3
-    - name: Mount bazel cache  # Optional
-      uses: actions/cache@v4
-      with:
-        path: "~/.cache/bazel"
-        key: bazel
-    - run: bazel build -c opt //:snmalloc
-    - run: bazel build -c opt //:snmalloc-rs
-
 
   # GitHub doesn't natively support *BSD, but we can run them in VMs on Mac /
   # Linux runners
@@ -503,13 +509,6 @@ jobs:
       run: cmake --build ${{github.workspace}}/build --target snmalloc-fuzzer
     - name: Test
       run: ${{github.workspace}}/build/fuzzing/snmalloc-fuzzer
-    - uses: bazelbuild/setup-bazelisk@v3
-    - name: Mount bazel cache  # Optional
-      uses: actions/cache@v4
-      with:
-        path: "~/.cache/bazel"
-        key: bazel
-    - run: bazel test -c opt --config=asan //fuzzing:snmalloc_fuzzer
 
   self-vendored:
     strategy:
@@ -535,6 +534,7 @@ jobs:
     - name: Prepare Windows
       if: runner.os == 'Windows'
       run: |
+        choco upgrade llvm
         choco install ninja
     - name: Prepare macOS
       if: runner.os == 'macOS'