Build/Test Tools: Remove hardcoded PHPUnit config files.

The configuration file passed to the callable workflow contains the correct one to use.

See #58955.

git-svn-id: https://develop.svn.wordpress.org/trunk@56831 602fd350-edb4-49c9-b593-d223f7449a82

.github/workflows/phpunit-tests-run.yml

@@ -159,11 +159,11 @@ jobs:
 
       - name: Run ms-files tests as a multisite install
         if: ${{ inputs.multisite }}
-        run: node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit --verbose -c tests/phpunit/multisite.xml --group ms-files
+        run: node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit --verbose -c ${{ env.PHPUNIT_CONFIG }} --group ms-files
 
       - name: Run external HTTP tests
         if: ${{ ! inputs.multisite }}
-        run: node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit --verbose -c phpunit.xml.dist --group external-http
+        run: node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit --verbose -c ${{ env.PHPUNIT_CONFIG }} --group external-http
 
       # __fakegroup__ is excluded to force PHPUnit to ignore the <exclude> settings in phpunit.xml.dist.
       - name: Run (Xdebug) tests