test: add copyright notice to typecheck.go
test: add copyright notice to typecheck.go

Also gofmt.

Change-Id: I36ac990965250867574f8e2318b65b87a0beda04
Reviewed-on: https://go-review.googlesource.com/c/go/+/228697
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

akutz/go,akutz/go,nawawi/go,akutz/go,golang/go,cloudflare/go,golang/go,cloudflare/go,akutz/go,nawawi/go,CAFxX/go,golang/go,akutz/go,nawawi/go,CAFxX/go,golang/go,golang/go,golang/go,cloudflare/go,CAFxX/go,akutz/go,cloudflare/go,akutz/go,nawawi/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,nawawi/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,cloudflare/go,nawawi/go,akutz/go,CAFxX/go