[release-branch.r57] 6g, 8g: fix goto fix

««« CL 4632041 / cbc2b570b2ca
6g, 8g: fix goto fix

R=ken2
CC=golang-dev
https://golang.org/cl/4632041
»»»

R=adg
CC=golang-dev
https://golang.org/cl/4631042