test: move debugger test case to parallel

Move test case that does not require a predetermined port to parallel.

test/parallel/test-debugger-unavailable-port.js

@@ -0,0 +1,36 @@
+'use strict';
+const common = require('../common');
+
+common.skipIfInspectorDisabled();
+
+const fixtures = require('../common/fixtures');
+const startCLI = require('../common/debugger');
+
+const assert = require('assert');
+const { createServer } = require('net');
+
+// Launch w/ unavailable port.
+(async () => {
+  const blocker = createServer((socket) => socket.end());
+  const port = await new Promise((resolve, reject) => {
+    blocker.on('error', reject);
+    blocker.listen(0, '127.0.0.1', () => resolve(blocker.address().port));
+  });
+
+  try {
+    const script = fixtures.path('debugger', 'three-lines.js');
+    const cli = startCLI([`--port=${port}`, script]);
+    const code = await cli.quit();
+
+    assert.doesNotMatch(
+      cli.output,
+      /report this bug/,
+      'Omits message about reporting this as a bug');
+    assert.ok(
+      cli.output.includes(`waiting for 127.0.0.1:${port} to be free`),
+      'Tells the user that the port wasn\'t available');
+    assert.strictEqual(code, 1);
+  } finally {
+    blocker.close();
+  }
+})().then(common.mustCall());

test/sequential/test-debugger-invalid-args.js

@@ -3,11 +3,9 @@ const common = require('../common');
 
 common.skipIfInspectorDisabled();
 
-const fixtures = require('../common/fixtures');
 const startCLI = require('../common/debugger');
 
 const assert = require('assert');
-const { createServer } = require('net');
 
 // Launch CLI w/o args.
 {
@@ -31,29 +29,3 @@ const { createServer } = require('net');
       assert.strictEqual(code, 1);
     });
 }
-
-// Launch w/ unavailable port.
-(async () => {
-  const blocker = createServer((socket) => socket.end());
-  const port = await new Promise((resolve, reject) => {
-    blocker.on('error', reject);
-    blocker.listen(0, '127.0.0.1', () => resolve(blocker.address().port));
-  });
-
-  try {
-    const script = fixtures.path('debugger', 'three-lines.js');
-    const cli = startCLI([`--port=${port}`, script]);
-    const code = await cli.quit();
-
-    assert.doesNotMatch(
-      cli.output,
-      /report this bug/,
-      'Omits message about reporting this as a bug');
-    assert.ok(
-      cli.output.includes(`waiting for 127.0.0.1:${port} to be free`),
-      'Tells the user that the port wasn\'t available');
-    assert.strictEqual(code, 1);
-  } finally {
-    blocker.close();
-  }
-})().then(common.mustCall());