test_runner: expose spec reporter as newable function

Fixes: #48112
Ref: #48208

lib/test/reporters.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { ObjectDefineProperties } = primordials;
+const { ObjectDefineProperties, ReflectConstruct } = primordials;
 
 let dot;
 let spec;
@@ -21,9 +21,9 @@ ObjectDefineProperties(module.exports, {
     __proto__: null,
     configurable: true,
     enumerable: true,
-    get() {
+    value: function value() {
       spec ??= require('internal/test_runner/reporter/spec');
-      return spec;
+      return ReflectConstruct(spec, arguments);
     },
   },
   tap: {

test/parallel/test-runner-run.mjs

@@ -82,15 +82,28 @@ describe('require(\'node:test\').run', { concurrency: true }, () => {
     ]);
   });
 
-  it('should be piped with spec', async () => {
-    const specReporter = new spec();
-    const result = await run({
-      files: [join(testFixtures, 'default-behavior/test/random.cjs')]
-    }).compose(specReporter).toArray();
-    const stringResults = result.map((bfr) => bfr.toString());
-    assert.match(stringResults[0], /this should pass/);
-    assert.match(stringResults[1], /tests 1/);
-    assert.match(stringResults[1], /pass 1/);
+  describe('should be piped with spec reporter', () => {
+    it('new spec', async () => {
+      const specReporter = new spec();
+      const result = await run({
+        files: [join(testFixtures, 'default-behavior/test/random.cjs')]
+      }).compose(specReporter).toArray();
+      const stringResults = result.map((bfr) => bfr.toString());
+      assert.match(stringResults[0], /this should pass/);
+      assert.match(stringResults[1], /tests 1/);
+      assert.match(stringResults[1], /pass 1/);
+    });
+
+    it('spec()', async () => {
+      const specReporter = spec();
+      const result = await run({
+        files: [join(testFixtures, 'default-behavior/test/random.cjs')]
+      }).compose(specReporter).toArray();
+      const stringResults = result.map((bfr) => bfr.toString());
+      assert.match(stringResults[0], /this should pass/);
+      assert.match(stringResults[1], /tests 1/);
+      assert.match(stringResults[1], /pass 1/);
+    });
   });
 
   it('should be piped with tap', async () => {