Fix match scrutinee not being dropped

[tothambrus11]

A match materializes its scrutinee into an owned local, but the block wrapping it is built with an empty cleanup list, so the local is never dropped.

When an arm binds the payload by reference the scrutinee stays live, so a resource-owning scrutinee leaks. The clearest case is a for-loop, which lowers to match next(it) { Some(x) => …, None => break } — the Option the iterator yields each iteration is never dropped.

The fix just adds the scrutinee local to the block's cleanup. The added test fails without it: the scrutinee's Probe drop never runs, so the recorded drop log is empty instead of 7.