cmd/ld: report pclntab, funcdata sizes in 6l -v output

   cmd/ld: report pclntab, funcdata sizes in 6l -v output
       Also move chatty recent additions to -v -v.

       For what it's worth:

       $ go build -o /dev/null -ldflags -v cmd/godoc
       ...
	0.73 pclntab=1259976 bytes, funcdata total 79788 bytes
       ...
       $

R=ken2
CC=cshapiro, golang-dev
https://golang.org/cl/12193043