C++: Merge the OverflowStatic tests.

Author: geoffw0

cpp/ql/test/query-tests/Critical/OverflowStatic/OverflowStatic.expected

@@ -1,3 +1,10 @@
+| test2.c:28:19:28:20 | 41 | Potential buffer-overflow: 'buffer' has size 40 not 41. |
+| test2.c:29:26:29:27 | 43 | Potential buffer-overflow: 'buffer' has size 40 not 43. |
+| test2.c:31:26:31:27 | 44 | Potential buffer-overflow: 'buffer' has size 40 not 44. |
+| test2.c:32:25:32:26 | 45 | Potential buffer-overflow: 'buffer' has size 40 not 45. |
+| test2.c:33:26:33:27 | 46 | Potential buffer-overflow: 'buffer' has size 40 not 46. |
+| test2.c:34:22:34:23 | 47 | Potential buffer-overflow: 'buffer' has size 40 not 47. |
+| test2.c:35:23:35:24 | 48 | Potential buffer-overflow: 'buffer' has size 40 not 48. |
 | test.c:14:9:14:13 | access to array | Potential buffer-overflow: 'xs' has size 5 but 'xs[5]' is accessed here. |
 | test.c:15:9:15:13 | access to array | Potential buffer-overflow: 'xs' has size 5 but 'xs[6]' is accessed here. |
 | test.c:20:9:20:18 | access to array | Potential buffer-overflow: 'ys' has size 5 but 'ys[5]' is accessed here. |