cmd/compile: use fmt.State in exprfmt
cmd/compile: use fmt.State in exprfmt

Change-Id: If6c2d469c66a7aa8471bf54310354efdac3e0235
Reviewed-on: https://go-review.googlesource.com/28337
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

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