Adopt Electron 1.7.x

[bpasero]

Currently blocked by: electron/electron#9696

[Tyriar]

Branch is at https://github.com/Microsoft/vscode/tree/electron/1.7.4

[Tyriar]

The --build arg is causing the issue on Windows. This:

.\scripts\test.bat --build --reporter dot

Calls %CODE% .\test\electron\index.js %* which passes --build to test\electron\index.js.

[Tyriar]

It may not work because out-build doesn't exist. I can repro when doing:

npm run watch
.\scripts\test.bat --build --reporter dot