cmd/go: hide the "TERM" environment variable from "go bug"
cmd/go: hide the "TERM" environment variable from "go bug"

Fixes #18128

Change-Id: I5530c9d774a1e398cd759a05bbf308e6e42f0007
Reviewed-on: https://go-review.googlesource.com/33810
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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