go.text/encoding: simplify charmapEncoder now that https://golang.org/cl/12087043/ "remove UTF-8 synchronization" has landed.
go.text/encoding: simplify charmapEncoder now that
https://golang.org/cl/12087043/ "remove UTF-8
synchronization" has landed.

R=r
CC=golang-dev
https://golang.org/cl/13185043

golang/text,cmars/tools,cmars/tools,cmars/tools,cmars/tools,npchp110/text