C++: Remove test for unrelated issue

The issue for that test is being tested and fixed on PR #2686. Adding a
test here will cause a semantic merge conflict.

Author: jbj

cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/defaulttainttracking.cpp

@@ -10,8 +10,8 @@ void sink(const char *);
 void sink(int);
 
 int main(int argc, char *argv[]) {
-  int taintedInt = atoi(getenv("VAR"));
-  taintedInt++; // BUG: `taintedInt` isn't marked as tainted. Only `++` is.
+
+
 
   sink(_strdup(getenv("VAR")));
   sink(strdup(getenv("VAR")));

cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/tainted.expected

@@ -1,9 +1,3 @@
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:1:22:1:25 | nptr |
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:13:7:13:16 | taintedInt |
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:13:20:13:23 | call to atoi |
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:13:25:13:30 | call to getenv |
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:13:25:13:37 | (const char *)... |
-| defaulttainttracking.cpp:13:25:13:30 | call to getenv | defaulttainttracking.cpp:14:3:14:14 | ... ++ |
 | defaulttainttracking.cpp:16:16:16:21 | call to getenv | defaulttainttracking.cpp:6:15:6:24 | p#0 |
 | defaulttainttracking.cpp:16:16:16:21 | call to getenv | defaulttainttracking.cpp:9:11:9:20 | p#0 |
 | defaulttainttracking.cpp:16:16:16:21 | call to getenv | defaulttainttracking.cpp:16:8:16:14 | call to _strdup |