container/heap: fix circular dependency in test
container/heap: fix circular dependency in test

Having the test be in the container/heap package yields a cycle
  container/heap (for the test)
  -> testing
  -> time
  -> container/heap (for timerHeap)

Occasionally the linker would get mixed up, resulting in a test panic
in a very weird place.

R=rsc, r2
CC=golang-dev
http://codereview.appspot.com/4395042

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

scirelli/scirelli-go,Triskite/willstone-goclone,npe9/noahevans-go9,npe9/noahevans-go9,mhennings/marcohennings-go,npe9/noahevans-go9,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,bryanxu/go-zh,d0f/go-zh,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,rdp/rogerpack2005-golang,mhennings/marcohennings-go,scirelli/scirelli-go,sanjosh/sanjos100-tipc,webfd/go-zh,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,npe9/noahevans-go9,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,d0f/go-zh,bryanxu/go-zh,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,sanjosh/sanjos100-tipc,webfd/go-zh,rdp/rogerpack2005-golang,Triskite/willstone-goclone,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,npe9/noahevans-go9,scirelli/scirelli-go,sanjosh/sanjos100-tipc,webfd/go-zh,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,sanjosh/sanjos100-tipc,webfd/go-zh,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,d0f/go-zh,mhennings/marcohennings-go,mhennings/marcohennings-go,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,bryanxu/go-zh,d0f/go-zh,d0f/go-zh,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,npe9/noahevans-go9,npe9/noahevans-go9,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,bryanxu/go-zh,rdp/rogerpack2005-golang,Triskite/willstone-goclone,Triskite/willstone-goclone,webfd/go-zh,webfd/go-zh,mhennings/marcohennings-go,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,scirelli/scirelli-go,npe9/noahevans-go9,webfd/go-zh,d0f/go-zh,rdp/rogerpack2005-golang,mhennings/marcohennings-go,d0f/go-zh,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,glycerine/jeaten-go-arrayof-structof,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,scirelli/scirelli-go,bryanxu/go-zh,bryanxu/go-zh