This PR is intentionally ugly. It duplicates all of the code in cli/js2/ into
cli/tsc/ ... because it's very important that we all understand that this code
is unnecessarily duplicated in our binary. I hope this ugliness provides the
motivation to clean it up.
The typescript git submodule is removed, because it's a very large repo and
contains all sorts of stuff we don't need. Instead the necessary files are
copied directly into the deno repo. Hence +200k lines.
COMPILER_SNAPSHOT.bin size
```
master 3448139
this branch 3320972
```
Fixes#6812
