cmd/go: don't write file if -n option is given
cmd/go: don't write file if -n option is given

Change-Id: I01f5d3b4748d0ead8642ff3e53d1ae9c4378bcbc
Reviewed-on: https://go-review.googlesource.com/61111
Reviewed-by: David Crawshaw <a2f0bf29257797dd66800b4fbb9945c3e216c004@golang.org>
Run-TryBot: David Crawshaw <a2f0bf29257797dd66800b4fbb9945c3e216c004@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

akutz/go,Cofyc/go,christopher-henderson/Go,golang/go,CAFxX/go,CAFxX/go,codestation/go,Cofyc/go,josharian/go,nawawi/go,Cofyc/go,cloudflare/go,cloudflare/go,CAFxX/go,nawawi/go,golang/go,Cofyc/go,CAFxX/go,polyverse-security/go,polyverse-security/go,josharian/go,CAFxX/go,golang/go,golang/go,josharian/go,polyverse-security/go,polyverse-security/go,nawawi/go,golang/go,nawawi/go,nawawi/go,polyverse-security/go,CAFxX/go,josharian/go,akutz/go,Cofyc/go,polyverse-security/go,Cofyc/go,josharian/go,cloudflare/go,josharian/go,codestation/go,codestation/go,josharian/go,nawawi/go,josharian/go,Cofyc/go,codestation/go,golang/go,cloudflare/go,cloudflare/go,codestation/go,CAFxX/go,polyverse-security/go,akutz/go,CAFxX/go,codestation/go,codestation/go,codestation/go,golang/go,akutz/go,cloudflare/go,akutz/go,nawawi/go,Cofyc/go,nawawi/go,golang/go,cloudflare/go,akutz/go,akutz/go,cloudflare/go,polyverse-security/go,akutz/go