Fix godoc deadlock.
Fix godoc deadlock.

The code was already careful not to use malloc/free
for stack growth during calls to malloc.
Avoid them during calls to free too.

R=r
DELTA=9  (7 added, 0 deleted, 2 changed)
OCL=29606
CL=29610

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