blocking_lock waiter count is wrong

[Thierry Delisle]

The pop_and_set_new_owner decrements the wait_count even if no thread was woken up.

void pop_and_set_new_owner( blocking_lock & this ) with( this ) {
	$thread * t = &dropHead( blocked_threads );
	owner = t;
	recursion_count = ( t ? 1 : 0 );
	wait_count--;
	unpark( t );
}