CI: In parse.y runs, use ./configure --with-parser=parse.y

Because tests might not use the command-line --parser option, or be
aware that they should be, it's better to test with the default
parser set.

Author: XrXr

.github/workflows/parsey.yml

@@ -69,7 +69,7 @@ jobs:
           dummy-files: ${{ matrix.test_task == 'check' }}
 
       - name: Run configure
-        run: ../src/configure -C --disable-install-doc cppflags=-DRUBY_DEBUG
+        run: ../src/configure -C --disable-install-doc cppflags=-DRUBY_DEBUG --with-praser=parse.y
 
       - run: make