test: deflake test-runner-watch-mode-kill-signal

Author: dario-piotrowicz

test/parallel/test-runner-watch-mode-kill-signal.mjs

@@ -23,7 +23,7 @@ const indexContents = `
   (async () => {
       // Wait a few milliseconds to make sure that the
       // parent process has time to attach its listeners
-      await setTimeout(200);
+      await setTimeout(${common.platformTimeout(300)});
 
       process.on('SIGTERM', () => {
           console.log('__SIGTERM received__');