tests: sv_queue_vec: Change base type to 4-state

The sv_queue_vec test uses queues of 2-state vectors, but also checks if
certain operations on the queue yield 'X.

2-state queues should never yield 'X and the test only passes because of a
bug. In preparation for fixing the bug change the test to use a 4-state
base type instead.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

ivtest/ivltests/sv_queue_vec.v

@@ -1,7 +1,7 @@
 module top;
-  int q_tst [$];
-  int q_tmp [$];
-  int elem;
+  integer q_tst [$];
+  integer q_tmp [$];
+  integer elem;
   integer idx;
   bit passed;