cgo[1-4].go, go1.go couldn't be tested now
(cgo[1-4].go can only be tested when cgo is enabled, go1.go
contain a list of filenames in the current directory)
R=golang-dev, alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/6218048
Also explain the situation with recursive String methods more accurately,
and clean up the code now that the fmt package is more careful.
R=golang-dev, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/5907047