runtime: convert type algorithms to Go

runtime: convert type algorithms to Go
Actually it mostly deletes code -- alg.print and alg.copy go away.
There was only one usage of alg.print for debug purposes.
Alg.copy is used in chan.goc, but Keith replaces them with
memcopy during conversion, so alg.copy is not needed as well.
Converting them would be significant amount of work
for no visible benefit.

LGTM=crawshaw, rsc, khr
R=golang-codereviews, crawshaw, khr
CC=golang-codereviews, rsc
https://golang.org/cl/139930044