C++: Make all the tests meaningful.

Author: geoffw0

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/inconsistentLoopDirection/inconsistentLoopDirection.cpp

@@ -190,8 +190,9 @@ void IntendedOverflow()
     for (i = 63; i < 255; i--) {} // GOOD
 
     for (i = m - 1; i < m; i--) {} // GOOD
-    for (i = m - 1; i < m; i--) {} // DUBIOUS
-    for (i = m - 1; i < m; i--) {} // GOOD
+    for (i = m - 2; i < m; i--) {} // DUBIOUS
+    for (i = m; i < m + 1; i--) {} // GOOD
 
     for (s = 63; s < 64; s--) {} // BAD (signed numbers don't wrap at 0 / at all)
+    for (s = m + 1; s < m; s--) {} // BAD (never runs)
 }

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/inconsistentLoopDirection/inconsistentLoopDirection.expected

@@ -21,3 +21,4 @@
 | inconsistentLoopDirection.cpp:175:5:175:36 | for(...;...;...) ... | Ill-defined for-loop: a loop using variable "i" counts downward from a value (0), but the terminal condition is higher (10). |
 | inconsistentLoopDirection.cpp:179:5:179:38 | for(...;...;...) ... | Ill-defined for-loop: a loop using variable "i" counts upward from a value (100), but the terminal condition is lower (0). |
 | inconsistentLoopDirection.cpp:196:5:196:32 | for(...;...;...) ... | Ill-defined for-loop: a loop using variable "s" counts downward from a value (63), but the terminal condition is higher (64). |
+| inconsistentLoopDirection.cpp:197:5:197:34 | for(...;...;...) ... | Ill-defined for-loop: a loop using variable "s" counts downward from a value (... + ...), but the terminal condition is always false. |