Fixes #1910. Fixes #1979. Fixes #1990. Fixes #1993. Fixes #2089. R=ken2 CC=golang-dev https://golang.org/cl/4828046
Remove now-unnecessary zeroing of stack frames. R=ken2 CC=golang-dev https://golang.org/cl/4641044
bug274.go:23:3: error: missing statement after label bug274.go:25:3: error: missing statement after label bug274.go:28:3: error: label ‘L2’ defined and not used R=rsc CC=golang-dev https://golang.org/cl/4273114
R=ken2 CC=golang-dev https://golang.org/cl/1742044