cmd/go: call flag.Parse to properly initialize test environment variables
Executing tests in cmd/go/internal/modfetch/gitrepo/fetch_test.go in enviroment
witout outside connectivity in to the internet results in tests failure:
2018/06/25 12:48:26 git clone --mirror https://vcs-test.golang.org/git/gitrepo1 /tmp/gitrepo-test-
221822392/gitrepo2 in : exit status 128:
Cloning into bare repository '/tmp/gitrepo-test-
221822392/gitrepo2'...
fatal: unable to access 'https://vcs-test.golang.org/git/gitrepo1/': Could not resolve host: vcs-test.golang.org
FAIL cmd/go/internal/modfetch/gitrepo 0.144s
Call flag.Parse in TestMain to properly initialize test environment variables
Fixes #26007
Change-Id: I059e27db69c0ca0e01db724035a25d6fefb094b5
Reviewed-on: https://go-review.googlesource.com/120735
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>