test: fs readfile, swap arguments in strictEqual

PR-URL: nodejs#24133
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

test/parallel/test-fs-readfile-fd.js

@@ -17,7 +17,7 @@ tempFd(function(fd, close) {
 
 tempFd(function(fd, close) {
   fs.readFile(fd, 'utf8', function(err, data) {
-    assert.strictEqual('', data);
+    assert.strictEqual(data, '');
     close();
   });
 });
@@ -27,7 +27,7 @@ tempFdSync(function(fd) {
 });
 
 tempFdSync(function(fd) {
-  assert.strictEqual('', fs.readFileSync(fd, 'utf8'));
+  assert.strictEqual(fs.readFileSync(fd, 'utf8'), '');
 });
 
 function tempFd(callback) {