buffer: rename internal/buffer_new.js to buffer.js

The old smalloc-based implementation has been removed, the typed array
implementation is the only one that is left now.

PR-URL: #2022
Reviewed-By: Rod Vagg <[email protected]>
Reviewed-By: Trevor Norris <[email protected]>

Author: bnoordhuis

lib/buffer.js

@@ -69,7 +69,6 @@
       'lib/vm.js',
       'lib/zlib.js',
       'lib/internal/child_process.js',
-      'lib/internal/buffer_new.js',
       'lib/internal/freelist.js',
       'lib/internal/socket_list.js',
       'lib/internal/repl.js',