cmd/go: make TestBuildDashIInstallsDependencies not depend only on time
cmd/go: make TestBuildDashIInstallsDependencies not depend only on time

When we make the go command pay attention to content
instead of time, we want this test to continue working.

Change-Id: Ib7d9d0d62bfe87810d71bdfc4f29561a8c70eccc
Reviewed-on: https://go-review.googlesource.com/56273
Run-TryBot: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

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