test: use Number.isNaN()

PR-URL: #17319
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-process-emit.js

@@ -19,4 +19,4 @@ process.emit('normal', 'normalData');
 process.emit(sym, 'symbolData');
 process.emit('SIGPIPE', 'signalData');
 
-assert.strictEqual(isNaN(process._eventsCount), false);
+assert.strictEqual(Number.isNaN(process._eventsCount), false);