Factor out sanitizer run.

Don't fail on sanitizer failure and provide separate CI jobs
for sanitizer builds.

.github/workflows/main.yml

@@ -78,10 +78,6 @@ jobs:
             dependencies: "sudo apt install ninja-build"
             extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10 -DCMAKE_CXX_FLAGS=-stdlib=libstdc++"
             build-only: yes
-          - os: "ubuntu-latest"
-            variant: Clang 10 libc++ (TSan + UBSan)
-            dependencies: "sudo apt install ninja-build"
-            extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_C_COMPILER=clang-10 -DCMAKE_CXX_FLAGS=-stdlib=libc++ -DSNMALLOC_SANITIZER=undefined,thread"
       # Don't abort runners if a single one fails
       fail-fast: false
     runs-on: ${{ matrix.os }}
@@ -114,6 +110,36 @@ jobs:
         ninja clean
         LD_PRELOAD=/usr/local/lib/libsnmallocshim-checks.so ninja
 
+  sanitizer:
+    strategy:
+      matrix:
+        # Build each combination of OS and release/debug variants
+        os: [ "ubuntu-latest"]
+        build-type: [ Release, Debug ]
+        include:
+          - os: "ubuntu-latest"
+            continue-on-error: # Don't class as an error if this fails, until we have a more reliablity.
+            variant: Clang 10 libc++ (TSan + UBSan)
+            dependencies: "sudo apt install ninja-build"
+            extra-cmake-flags: "-DCMAKE_CXX_COMPILER=clang++-10 -DCMAKE_CXX_FLAGS=-stdlib=\"libc++ -g\" -DSNMALLOC_SANITIZER=undefined,thread"
+      # Don't abort runners if a single one fails
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    name: ${{ matrix.os }} ${{ matrix.build-type }} ${{ matrix.variant }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install build dependencies
+      run: ${{ matrix.dependencies }}
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -G Ninja ${{ matrix.cmake-flags }} ${{ matrix.extra-cmake-flags }}
+      # Build with a nice ninja status line
+    - name: Build
+      working-directory: ${{github.workspace}}/build
+      run: NINJA_STATUS="%p [%f:%s/%t] %o/s, %es" ninja
+    - name: Test
+      working-directory: ${{github.workspace}}/build
+      run: ctest --output-on-failure -j 4 -C ${{ matrix.build-type }} --timeout 400 -E "memcpy|external_pointer" --repeat-until-fail 2
+
   qemu-crossbuild:
     strategy:
       matrix: