doc: remove remaining cmd/go entries from go1.8.txt
doc: remove remaining cmd/go entries from go1.8.txt

None of them need to be called out in the release notes.

Change-Id: I143a1879b25063574e4107c1e89264434d45d1d5
Reviewed-on: https://go-review.googlesource.com/33676
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

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