remove unused interface tests (#4247)

* Remove bdd.spec.js and tdd.spec.js

These tests are deprecated. Only a few tests in the last of the files
that checks clear cases were running. Since there are integration
tests that checks the `only` behavior in integration/only.spec.js,
it's okay to remove these tests.

* Remove qunit.spec.js

qunit.spec.js was not exeuced in `npm run test`. Also there are
integration tests for the qunit in integration/only.spec.js.

* Remove unused bdd.spec.js and tdd.spec.js

package-scripts.js

@@ -158,8 +158,6 @@ module.exports = {
         only: {
           default: {
             script: `nps ${[
-              'test.node.only.bdd',
-              'test.node.only.tdd',
               'test.node.only.bddRequire',
               'test.node.only.globalBdd',
               'test.node.only.globalTdd',
@@ -168,22 +166,6 @@ module.exports = {
             description: 'Run Node.js "only" functionality tests',
             hiddenFromHelp: true
           },
-          bdd: {
-            script: test(
-              'only-bdd',
-              '--ui bdd test/only/bdd.spec --no-parallel'
-            ),
-            description: 'Run Node.js "only" w/ BDD interface tests',
-            hiddenFromHelp: true
-          },
-          tdd: {
-            script: test(
-              'only-tdd',
-              '--ui tdd test/only/tdd.spec --no-parallel'
-            ),
-            description: 'Run Node.js "only" w/ TDD interface tests',
-            hiddenFromHelp: true
-          },
           bddRequire: {
             script: test(
               'only-bdd-require',