test: refactor test-async-wrap-check-providers

* use 'strictEqual' instead of 'equal'
* use '!==' instead of '!='

PR-URL: https://github.com/nodejs/node/pull/9297
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-async-wrap-check-providers.js

@@ -31,7 +31,7 @@ if (common.isAix) {
 }
 
 function init(id, provider) {
-  keyList = keyList.filter((e) => e != pkeys[provider]);
+  keyList = keyList.filter((e) => e !== pkeys[provider]);
 }
 
 function noop() { }
@@ -114,6 +114,6 @@ process.on('exit', function() {
   if (keyList.length !== 0) {
     process._rawDebug('Not all keys have been used:');
     process._rawDebug(keyList);
-    assert.equal(keyList.length, 0);
+    assert.strictEqual(keyList.length, 0);
   }
 });