before:

  $ npx ./bench/run.sh
  real    0m0.874s
  user    0m1.219s
  sys     0m0.060s

Of that, 470ms were spent in `insert-module-globals`.

after:

  $ npx ./bench/run.sh
  real    0m0.580s
  user    0m0.863s
  sys     0m0.056s

Of that, 220ms were spent in `insert-module-globals`.

To make sure that all the parsing in browserify happens in modules
under the browserify org; this way anyone in the browserify github org
can upgrade to newer parser versions if necessary.