Version 1.2.3 breaks non-browserify cypress setup

[SBoudrias]

The release 1.2.3 appear to be forcing the default browserify preprocessor. b36fb9c#diff-7aa2d6e03c8f7e1334d6724f903c6819R26

This breaks our project using @cypress/preprocessor-webpack because no processing is done; so the JS syntax isn't valid and throw a parsing exception.

[meinaart]

I was afraid of that this would break something :(. I think I just have to break the support for "Running all tests" again to fix your issue.

I reported a bug to address the underlying issue for "All tests":
cypress-io/cypress#3090

[SBoudrias]

Thanks for being so responsive on issues we're raising 😄