Clarify that Condition::wait() can spuriously wake up

Also, remove the clarification that Condition::signal() wakes exactly
one thread as in the presence of spurious wake ups, this clarification
does not provide a safe guarantee to developers.

Bug: 34592766
Test: Build
Change-Id: I34df02e44a70a18fe04ceda858d002ef129c1fd9
1 file changed