test: add crypto check to test-http2-debug

This commit adds a crypto check to test-http2-debug.js as it currently
will error if configured --without-ssl.

The issue here is that the while the test spawns a child process that
runs test-http2-ping.js, which does have a crypto check, it will just
print '1..0 # Skipped: missing crypto' to stdout, and nothing to stderr
which is what this test is trying to assert and hence failing.

test/parallel/test-http2-debug.js

@@ -1,5 +1,7 @@
 'use strict';
-require('../common');
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
 const assert = require('assert');
 const child_process = require('child_process');
 const path = require('path');