install: failing to parse package.json should be error

[watilde]

Fixes #12155. We can stop install process when the EJSONPARSE error happened, because the process never finish if npm can't parse package.json.

[iarna]

I'm merging this as 2010d18. I did two things:

1. I squashed the test and change commits–I like to see patches in the same commit as the patch they support. Having them together makes later searching through the commit log easier because if git blame leads me to a commit id, git show will show me everything relevant.
2. I rewrote the test to match our newer house style. We haven't documented this much anywhere, but I encourage you to take a look, the primary changes are using tacks to setup and cleanup our test case and throwing if the err arg from common.npm exists. We do the latter because that is only set if common.npm couldn't exec npm for some reason, usually an OS problem. It's never an error in the software being tested, but a problem with the machine running the tests.

[watilde]

Thanks for letting me know them! The newer house style seems neat. Will try to read some the other tests and use it next time.

[iarna]

Merged into v3.8.8!