fix: output directly to args.gn

[dsanders11]

Fixes #582.

With the changes in #581, a shell is now being used to execute gn.bat on Windows and as a result the GN arguments are no longer interpreted correctly (due to spaces between arguments). Seemed simplest to dump them directly into args.gn rather than escape quotes and potentially miss some corner cases.

[ppontes]

If I try this branch to go around #582 with a freshly initialized repo, I now get:

e build
ERROR Error: ENOENT: no such file or directory, open '(...)\src\out\Testing\args.gn'

[VerteDinde]

Just saw Pedro's comment - this branch seems to be working for me on Windows, but let me try creating a new checkout

[mlaurencin]

I ran into the same issue as Pedro, but rather than with a fresh repo specifically, I was just trying to pull down and build a new remote branch.

[dsanders11]

Should be fixed now, that case where the outDir didn't exist yet wasn't being handled, and now is. Thanks for the heads up!