[dev.ssa] cmd/compile/ssa: Replace less-or-equal with equal in len comparison with zero
[dev.ssa] cmd/compile/ssa: Replace less-or-equal with equal in len comparison with zero

Since the spec guarantees than 0 <= len always:

https://golang.org/ref/spec#Length_and_capacity

replace len(...) <= 0 check with len(...) == 0 check

Change-Id: I5517a9cb6b190f0b1ee314a67487477435f3b409
Reviewed-on: https://go-review.googlesource.com/12034
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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