[dev.ssa] cmd/compile/ssa: print lazily
[dev.ssa] cmd/compile/ssa: print lazily

Reduces 'go run run.go 64bit.go' from 23s to 8s on my machine.

Change-Id: Ie5b642d0abb56e8eb3899d69472bc88a85a1c985
Reviewed-on: https://go-review.googlesource.com/12023
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

polyverse-security/go,momchil-velikov/go,Cofyc/go,cyberroadie/go,Samurais/go,suncycheng/go,polyverse-security/go,cloudflare/go,vanloswang/go,cyberroadie/go,vsekhar/elastic-go,linux-on-ibm-z/go,linux-on-ibm-z/go,linux-on-ibm-z/go,Cofyc/go,akutz/go,Cofyc/go,golang/go,miolini/go,ImJasonH/go,Cofyc/go,momchil-velikov/go,golang/go,vanloswang/go,theif519/go,derekmarcotte/go,4ad/go,CAFxX/go,momchil-velikov/go,mwhudson/go,derekmarcotte/go,suncycheng/go,mwhudson/go,derekmarcotte/go,vsekhar/elastic-go,nawawi/go,4ad/go,ganboing/go-esx,linux-on-ibm-z/go,vanloswang/go,vsekhar/elastic-go,CAFxX/go,nawawi/go,theif519/go,goodlang/good,Cofyc/go,miolini/go,mwhudson/go,ImJasonH/go,golang/go,vanloswang/go,codestation/go,CAFxX/go,theif519/go,Cofyc/go,akutz/go,akutz/go,akutz/go,cloudflare/go,miolini/go,goodlang/good,miolini/go,golang/go,suncycheng/go,linux-on-ibm-z/go,4ad/go,akutz/go,ganboing/go-esx,mwhudson/go,polyverse-security/go,Cofyc/go,momchil-velikov/go,4ad/go,binarycrusader/go,suncycheng/go,polyverse-security/go,miolini/go,nawawi/go,ganboing/go-esx,nawawi/go,CAFxX/go,nawawi/go,theif519/go,ImJasonH/go,4ad/go,momchil-velikov/go,momchil-velikov/go,mwhudson/go,binarycrusader/go,ganboing/go-esx,suncycheng/go,christopher-henderson/Go,ganboing/go-esx,vsekhar/elastic-go,ImJasonH/go,miolini/go,vsekhar/elastic-go,codestation/go,CAFxX/go,akutz/go,Cofyc/go,cyberroadie/go,ganboing/go-esx,cyberroadie/go,ImJasonH/go,vanloswang/go,CAFxX/go,mwhudson/go,binarycrusader/go,goodlang/good,josharian/go,ImJasonH/go,binarycrusader/go,golang/go,derekmarcotte/go,vsekhar/elastic-go,cloudflare/go,4ad/go,cyberroadie/go,cloudflare/go,4ad/go,nawawi/go,cloudflare/go,ganboing/go-esx,goodlang/good,josharian/go,momchil-velikov/go,vsekhar/elastic-go,josharian/go,akutz/go,codestation/go,binarycrusader/go,4ad/go,ganboing/go-esx,derekmarcotte/go,goodlang/good,cloudflare/go,mwhudson/go,miolini/go,akutz/go,binarycrusader/go,polyverse-security/go,CAFxX/go,vanloswang/go,josharian/go,polyverse-security/go,binarycrusader/go,codestation/go,josharian/go,josharian/go,Samurais/go,linux-on-ibm-z/go,vanloswang/go,Samurais/go,cyberroadie/go,goodlang/good,suncycheng/go,CAFxX/go,Samurais/go,codestation/go,nawawi/go,codestation/go,derekmarcotte/go,derekmarcotte/go,linux-on-ibm-z/go,momchil-velikov/go,cloudflare/go,Samurais/go,miolini/go,nawawi/go,goodlang/good,polyverse-security/go,theif519/go,codestation/go,mwhudson/go,theif519/go,cyberroadie/go,cyberroadie/go,ImJasonH/go,golang/go,theif519/go,polyverse-security/go,derekmarcotte/go,linux-on-ibm-z/go,ImJasonH/go,Samurais/go,josharian/go,golang/go,cloudflare/go,Samurais/go,codestation/go,goodlang/good,binarycrusader/go,vsekhar/elastic-go,Samurais/go,suncycheng/go,josharian/go,golang/go,vanloswang/go,theif519/go,suncycheng/go