build: test multi-config generator (#22310)

Multi-config generators can be tricky so testing them would be good.
Also test GCC release and MinSizeRel build types as they're prone to
unusual warnings. Remove release testing from test.yml as this is a
sufficient replacement.

.github/workflows/test.yml

@@ -140,10 +140,6 @@ jobs:
             cc: gcc
             runner: ubuntu-22.04
             flags: -D UNSIGNED_CHAR=ON
-          - flavor: release
-            cc: gcc
-            runner: ubuntu-22.04
-            flags: -D CMAKE_BUILD_TYPE=Release
           - cc: clang
             runner: macos-12
 
@@ -210,7 +206,7 @@ jobs:
         id: abort_job
         run: echo "status=${{ job.status }}" >> $GITHUB_OUTPUT
 
-      - if: matrix.flavor != 'tsan' && matrix.flavor != 'release' && matrix.flavor != 'functionaltest-lua' && (success() || failure() && steps.abort_job.outputs.status == 'success')
+      - if: matrix.flavor != 'tsan' && matrix.flavor != 'functionaltest-lua' && (success() || failure() && steps.abort_job.outputs.status == 'success')
         name: Unittest
         timeout-minutes: 5
         run: cmake --build build --target unittest