gosrc: re-generate std lib for 1.9
gosrc: re-generate std lib for 1.9

Change-Id: I9d5d6df05cd0dfa094074668b0911fb18edbb927
Reviewed-on: https://go-review.googlesource.com/58612
Reviewed-by: Stephen Weinberg <9c6f45be7f163ae13ead4fcb29aeb9763375e17f@google.com>

segmentio/gddo,segmentio/gddo,golang/gddo,segmentio/gddo,golang/gddo,golang/gddo,golang/gddo,segmentio/gddo