_js: use gopherjs/js.MakeFullWrapper
_js: use gopherjs/js.MakeFullWrapper

From @myitcv's fork of GopherJS at https://github.com/myitcv/gopherjs.

It doesn't look like this "full" wrapping will be merged into upstream
GopherJS anytime soon, so it's best to stick with the fork than the pull
request. This also means that it's clear what the wrapping does, and the
fork doesn't break backwards compatibility.

mvdan/sh,mvdan/sh,mvdan/sh,mvdan/sh