With the goal of centralizing all tests in the system, this is a
first step to establish a Tests sub-tree. It will contain all of
the unit tests and test harnesses for the various components in the
system.
Add a test case that the timeout argument to pthread_cond_timedwait
works in LibPthread. This change also validates the new support for
timeouts to the futex syscall, as that's how condition variables are
implemented.
