cmd/compile: better variable names in internal/syntax/branches.go
cmd/compile: better variable names in internal/syntax/branches.go

Follow-up on https://go-review.googlesource.com/#/c/39998/.

Change-Id: I97f8e31ca923685198984ad64f952d6dc8208edf
Reviewed-on: https://go-review.googlesource.com/40982
Run-TryBot: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Reviewed-by: Marvin Stenger <bde3f4ccdd7c08fc2bda30f654959132eeced9b3@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

Cofyc/go,derekmarcotte/go,Cofyc/go,ImJasonH/go,codestation/go,akutz/go,polyverse-security/go,cloudflare/go,akutz/go,codestation/go,josharian/go,cloudflare/go,vsekhar/elastic-go,golang/go,golang/go,nawawi/go,ImJasonH/go,golang/go,nawawi/go,golang/go,derekmarcotte/go,josharian/go,cloudflare/go,CAFxX/go,vsekhar/elastic-go,golang/go,cloudflare/go,derekmarcotte/go,Cofyc/go,vsekhar/elastic-go,polyverse-security/go,ImJasonH/go,nawawi/go,ImJasonH/go,josharian/go,nawawi/go,Cofyc/go,CAFxX/go,polyverse-security/go,Cofyc/go,josharian/go,polyverse-security/go,derekmarcotte/go,Cofyc/go,polyverse-security/go,CAFxX/go,derekmarcotte/go,polyverse-security/go,codestation/go,CAFxX/go,polyverse-security/go,derekmarcotte/go,vsekhar/elastic-go,Cofyc/go,ImJasonH/go,josharian/go,derekmarcotte/go,cloudflare/go,golang/go,akutz/go,ImJasonH/go,akutz/go,christopher-henderson/Go,vsekhar/elastic-go,cloudflare/go,akutz/go,CAFxX/go,CAFxX/go,akutz/go,codestation/go,cloudflare/go,polyverse-security/go,josharian/go,josharian/go,nawawi/go,akutz/go,vsekhar/elastic-go,codestation/go,ImJasonH/go,nawawi/go,CAFxX/go,codestation/go,ImJasonH/go,golang/go,nawawi/go,golang/go,akutz/go,cloudflare/go,derekmarcotte/go,vsekhar/elastic-go,josharian/go,CAFxX/go,codestation/go,vsekhar/elastic-go,codestation/go,Cofyc/go,nawawi/go