This patch adds the sanitizer_start_switch_fiber and
sanitizer_finish_switch_fiber methods inspired from what can be found here
These methods are needed when the compiled software needs to implement
coroutines, fibers or the like. Without a way to annotate them, when the program
jumps to a stack that is not the thread stack, __asan_handle_no_return shows a
warning about that, and the fake stack mechanism may free fake frames that are
still in use.