test: fix test/pummel/test-fs-watch-non-recursive.js

test-fs-watch-non-recursive was loading the `common/tmpdir` module as if
it were a built-in and was failing because of it. Fix the path. The test
now works.

PR-URL: nodejs#25386
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/pummel/test-fs-watch-non-recursive.js

@@ -24,7 +24,7 @@ const common = require('../common');
 const path = require('path');
 const fs = require('fs');
 
-const tmpdir = require('tmpdir');
+const tmpdir = require('../common/tmpdir');
 
 const testDir = tmpdir.path;
 const testsubdir = path.join(testDir, 'testsubdir');