tests: fix lef_shift test

vlib/v/checker/tests/inout/left_shift_err.out

@@ -1,6 +1,6 @@
 vlib/v/checker/tests/inout/left_shift_err.v:3:7: error: cannot shift type string into array_int
     1| fn main() {
-    2|     l := []int
+    2|     l := []int{}
     3|     l << 'test'
                 ~~~~~~
     4| }