8140520: segfault on solaris-amd64 with "-XX:VMThreadStackSize=1" option
Summary: Split the single thread_min_stack_allowed into three distinct values (java_thread_min_stack_allowed, compiler_thread_min_stack_allowed and vm_internal_thread_min_stack_allowed) on non-Windows platforms.
Reviewed-by: dcubed, gthornbr, dholmes, coleenp, fparain, aph