C++: Fix 'isDebugMode'. It was computing 'isNotDebugMode' (oops).

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll

@@ -487,7 +487,7 @@ class Node extends TIRDataFlowNode {
 }
 
 private string toExprString(Node n) {
-  isDebugMode() and
+  not isDebugMode() and
   (
     result = n.asExpr(0).toString()
     or

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/Node0ToString.qll

@@ -72,4 +72,4 @@ string instructionToString(Instruction i) { result = any(Node0ToString nts).inst
  * In debug mode the `toString` on dataflow nodes is more expensive to compute,
  * but gives more precise information about the different dataflow nodes.
  */
-predicate isDebugMode() { not any(Node0ToString nts).isDebugMode() }
+predicate isDebugMode() { any(Node0ToString nts).isDebugMode() }