test: remove string literals for strictEquals/notStrictEquals

In short: Some unit tests are using string literals to simply tell you a
conclusion what's right/wrong BUT not tell you what actually values are.
So it's necessary to print them out in the console.

Refs: #22849
PR-URL: #22891
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/fixtures/not-main-module.js

@@ -20,6 +20,5 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 const assert = require('assert');
-assert.notStrictEqual(module, require.main, 'require.main should not == module');
-assert.notStrictEqual(module, process.mainModule,
-                      'process.mainModule should not === module');
+assert.notStrictEqual(module, require.main);
+assert.notStrictEqual(module, process.mainModule);

test/parallel/test-async-wrap-trigger-id.js

@@ -11,18 +11,18 @@ let triggerAsyncId1;
 process.nextTick(() => {
   process.nextTick(() => {
     triggerAsyncId1 = triggerAsyncId();
+    // Async resources having different causal ancestry
+    // should have different triggerAsyncIds
     assert.notStrictEqual(
       triggerAsyncId0,
-      triggerAsyncId1,
-      'Async resources having different causal ancestry ' +
-      'should have different triggerAsyncIds');
+      triggerAsyncId1);
   });
   process.nextTick(() => {
     const triggerAsyncId2 = triggerAsyncId();
+    // Async resources having the same causal ancestry
+    // should have the same triggerAsyncId
     assert.strictEqual(
       triggerAsyncId1,
-      triggerAsyncId2,
-      'Async resources having the same causal ancestry ' +
-      'should have the same triggerAsyncId');
+      triggerAsyncId2);
   });
 });