Merge macOS CIs to reduce concurrency

On GitHub Actions, the macOS runners seem much more expensive than
Ubuntu, and its limit is the most significant bottlenecks for our
CIs.  As the "check" tasks usually finish 3 or 4 times faster than
"test-bundler-parallel", it will be balanced by running all three
"check" tasks sequentially.

.github/workflows/macos.yml

@@ -19,6 +19,7 @@ jobs:
         test_task: [ "check", "test-bundler-parallel" ] #, "test-bundled-gems" ] matrix tests has unknown issues
       fail-fast: false
     env:
+      RUBY_TESTOPTS: '-q --tty=no'
       GITPULLOPTIONS: --no-tags origin ${{github.ref}}
     runs-on: ${{ matrix.os }}
     steps:
@@ -52,8 +53,13 @@ jobs:
       - run: make -s ${{ matrix.test_task }}
         timeout-minutes: ${{ matrix.test_task == 'check' && 15 || 40 }}
         env:
-          RUBY_TESTOPTS: "-q --tty=no"
           TEST_BUNDLED_GEMS_ALLOW_FAILURES: "rexml"
+      - run: make -s check RUN_OPTS="--yjit"
+        timeout-minutes: 60
+        if: ${{ matrix.test_task == 'check' }}
+      - run: make -s check RUN_OPTS="--yjit --yjit-call-threshold=1 --yjit-max-versions=1"
+        timeout-minutes: 60
+        if: ${{ matrix.test_task == 'check' }}
       - uses: k0kubun/action-slack@v2.0.0
         with:
           payload: |