should care about the case that given arguments are less then mandatory formal...

should care about the case that given arguments are less then mandatory formal arguments and optional arguments exist; close #2144

src/vm.c

@@ -1303,7 +1303,7 @@ RETRY_TRY_BLOCK:
         if (r) {
           regs[m1+o+1] = mrb_ary_new_capa(mrb, 0);
         }
-        if (o == 0) pc++;
+        if (o == 0 || argc < m1+m2) pc++;
         else
           pc += argc - m1 - m2 + 1;
       }