test: fix flaky test-force-repl

test/parallel/test-force-repl.js has an unnecessary timer that makes the
test flaky under load. Remove it.

test/parallel/test-force-repl.js

@@ -3,16 +3,13 @@ const common = require('../common');
 const assert = require('assert');
 const spawn = require('child_process').spawn;
 
-// spawn a node child process in "interactive" mode (force the repl)
+// Spawn a node child process in interactive mode (enabling the REPL) and
+// confirm the '> ' prompt is included in the output.
 const cp = spawn(process.execPath, ['-i']);
-// give node + the repl 5 seconds to start
-const timeoutId = setTimeout(common.mustNotCall(),
-                             common.platformTimeout(5000));
 
 cp.stdout.setEncoding('utf8');
 
 cp.stdout.once('data', common.mustCall(function(b) {
-  clearTimeout(timeoutId);
   assert.strictEqual(b, '> ');
   cp.kill();
 }));