Merge pull request #5629 from rocallahan/remove-zero-wires

Avoid scanning entire module in `Module::remove()` if there are no wires to remove

kernel/rtlil.cc

@@ -2990,6 +2990,8 @@ void RTLIL::Module::add(RTLIL::Binding *binding)
 void RTLIL::Module::remove(const pool<RTLIL::Wire*> &wires)
 {
 	log_assert(refcount_wires_ == 0);
+	if (wires.empty())
+		return;
 
 	struct DeleteWireWorker
 	{