Check arg count

Co-authored-by: Ralf Jung <post@ralfj.de>

src/shims/intrinsics.rs

@@ -655,6 +655,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             "try" => return this.handle_try(args, dest, ret),
 
             "breakpoint" => {
+                let &[] = check_arg_count(args)?;
                 // normally this would raise a SIGTRAP, which aborts if no debugger is connected
                 throw_machine_stop!(TerminationInfo::Abort("Trace/breakpoint trap".to_string()))
             }