cmd/go: add version of GOROOT to go bug details
cmd/go: add version of GOROOT to go bug details

Fixes #15877.

Change-Id: Ia1e327c0cea3be43e5f8ba637c97c223cee4bb5a
Reviewed-on: https://go-review.googlesource.com/32643
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Run-TryBot: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/go,linux-on-ibm-z/go,suncycheng/go,CAFxX/go,cloudflare/go,golang/go,vsekhar/elastic-go,CAFxX/go,golang/go,Cofyc/go,linux-on-ibm-z/go,cloudflare/go,codestation/go,derekmarcotte/go,nawawi/go,linux-on-ibm-z/go,goodlang/good,josharian/go,polyverse-security/go,Cofyc/go,polyverse-security/go,vsekhar/elastic-go,akutz/go,vsekhar/elastic-go,codestation/go,ImJasonH/go,nawawi/go,goodlang/good,CAFxX/go,codestation/go,nawawi/go,linux-on-ibm-z/go,codestation/go,goodlang/good,polyverse-security/go,suncycheng/go,akutz/go,ImJasonH/go,derekmarcotte/go,Cofyc/go,vsekhar/elastic-go,akutz/go,goodlang/good,akutz/go,suncycheng/go,goodlang/good,suncycheng/go,CAFxX/go,golang/go,akutz/go,suncycheng/go,ImJasonH/go,linux-on-ibm-z/go,ImJasonH/go,josharian/go,nawawi/go,vsekhar/elastic-go,suncycheng/go,CAFxX/go,derekmarcotte/go,ImJasonH/go,josharian/go,derekmarcotte/go,linux-on-ibm-z/go,cloudflare/go,codestation/go,ImJasonH/go,derekmarcotte/go,suncycheng/go,suncycheng/go,codestation/go,goodlang/good,vsekhar/elastic-go,golang/go,golang/go,polyverse-security/go,derekmarcotte/go,akutz/go,Cofyc/go,nawawi/go,derekmarcotte/go,josharian/go,polyverse-security/go,polyverse-security/go,linux-on-ibm-z/go,goodlang/good,golang/go,nawawi/go,codestation/go,vsekhar/elastic-go,akutz/go,cloudflare/go,josharian/go,polyverse-security/go,nawawi/go,cloudflare/go,cloudflare/go,akutz/go,goodlang/good,derekmarcotte/go,codestation/go,Cofyc/go,CAFxX/go,nawawi/go,josharian/go,linux-on-ibm-z/go,Cofyc/go,josharian/go,CAFxX/go,cloudflare/go,Cofyc/go,golang/go,ImJasonH/go,CAFxX/go,josharian/go,christopher-henderson/Go,cloudflare/go,polyverse-security/go,ImJasonH/go,vsekhar/elastic-go,Cofyc/go