Skip test-all for debug builds too

* It's very slow and not so worthwhile, the point
  to run test-all is to catch broken CRuby master,
  for which running test-all for the regular builds should be enough.

Author: eregon

.github/workflows/build.yml

@@ -235,7 +235,7 @@ jobs:
     # Test
     - run: make test-spec MSPECOPT=-j
     - run: make test-all TESTS="-j4"
-      if: "!contains(matrix.name, 'asan')"
+      if: "!contains(matrix.name, 'asan') && matrix.name != 'debug'"
 
     - run: echo "$HOME/.rubies/ruby-${{ matrix.name }}/bin" >> $GITHUB_PATH
     - uses: actions/checkout@v6