[dev.ssa] cmd/compile/internal/ssa: fix fallthrough return
[dev.ssa] cmd/compile/internal/ssa: fix fallthrough return

Fallthrough return needs to be a return block before jumping
to the exit block.

Change-Id: I994de2064da5c326c9cade2c33cbb15bdbce5acb
Reviewed-on: https://go-review.googlesource.com/14256
Reviewed-by: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>

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