test: use descriptive name for destination file

`http2-url-tests.js` is misleading. Use the same name of the source file
instead.

Author: lpinca

test/parallel/test-http2-pipe-named-pipe.js

@@ -15,7 +15,7 @@ const path = require('path');
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();
 const loc = fixtures.path('person-large.jpg');
-const fn = path.join(tmpdir.path, 'http2-url-tests.js');
+const fn = path.join(tmpdir.path, 'person-large.jpg');
 
 const server = http2.createServer();