cont.c (fiber_memsize): do not rely on ROOT_FIBER_CONTEXT
We can check if the fiber we're interested in is the
th->root_fiber for the owner thread, so there is no need to use
ROOT_FIBER_CONTEXT.
Note: there is no guarantee th->ec points to
&th->root_fiber->cont.saved_ec, thus vm::thread_memsize may not
account for root fiber correctly (pre-existing bug).
cont.c (fiber_memsize): do not rely on ROOT_FIBER_CONTEXT
We can check if the fiber we're interested in is the
th->root_fiber for the owner thread, so there is no need to use
ROOT_FIBER_CONTEXT.
Note: there is no guarantee th->ec points to
&th->root_fiber->cont.saved_ec, thus vm::thread_memsize may not
account for root fiber correctly (pre-existing bug).
[Bug #15050]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64705 b2dd03c8-39d4-4d8f-98ff-823fe69b080e