Set at least PTHREAD_STACK_MIN stack size when creating threads.
This patch makes sure, that the stack size of the new threads are never
less than PTHREAD_STACK_MIN, otherwise the pthread_attr_setstacksize()
function sets the default stack size (8MB), which leads to failure
in the BootUpMemoryUse test.
TEST=cctest/test-mark-compact/BootUpMemoryUse
BUG=
R=yangguo@chromium.org
Review URL: https://codereview.chromium.org/
63183003
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17610
ce2b1a6d-e550-0410-aec6-
3dcde31c8c00