misc/pprof: fix address lookup regression on Linux
misc/pprof: fix address lookup regression on Linux

Just use "go tool addr2line" no matter what, since we know
it works for all OSs.

Fixes issue 4818.

R=rsc, r
CC=golang-dev
https://codereview.appspot.com/7526047

Committer: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

sanjosh/sanjos100-tipc,webfd/go-zh,d0f/go-zh,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,scirelli/scirelli-go,mhennings/marcohennings-go,webfd/go-zh,rdp/rogerpack2005-golang,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,scirelli/scirelli-go,bryanxu/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,sanjosh/sanjos100-tipc,scirelli/scirelli-go,rdp/rogerpack2005-golang,webfd/go-zh,bryanxu/go-zh,webfd/go-zh,scirelli/scirelli-go,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,mhennings/marcohennings-go,bryanxu/go-zh,d0f/go-zh,rdp/rogerpack2005-golang,webfd/go-zh,bryanxu/go-zh,mhennings/marcohennings-go,d0f/go-zh,webfd/go-zh,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,rdp/rogerpack2005-golang,mhennings/marcohennings-go,webfd/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,scirelli/scirelli-go,scirelli/scirelli-go,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,d0f/go-zh,bryanxu/go-zh,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,d0f/go-zh,bryanxu/go-zh