test: remove --no-crankshaft

The option `--no-crankshaft` is no longer available as of V8 6.0

PR-URL: nodejs#14531
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

test/parallel/test-crypto-dh-leak.js

@@ -1,4 +1,4 @@
-// Flags: --expose-gc --nocrankshaft --noconcurrent_recompilation
+// Flags: --expose-gc --noconcurrent_recompilation
 'use strict';
 
 const common = require('../common');