cmd/compile: remove commented-out old c code
cmd/compile: remove commented-out old c code

Change-Id: I9b2e6c45f7e83543a06d0aafd08a911f7b6485fd
Reviewed-on: https://go-review.googlesource.com/29874
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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