cmd/vet: silence error from type checker unless verbose is set. Also restores the checking of _test.go files, which disappeared as a result of the package-at-a-time change. Fixes issue 4895.
cmd/vet: silence error from type checker unless verbose is set.
Also restores the checking of _test.go files, which disappeared
as a result of the package-at-a-time change.
Fixes issue 4895.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/7399051

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang