C++: Delete the fix that was introduced in bb447d7. This is no longer needed after github#5678.

Author: MathiasVP

cpp/ql/src/semmle/code/cpp/security/Overflow.qll

@@ -99,12 +99,11 @@ VariableAccess varUse(LocalScopeVariable v) { result = v.getAnAccess() }
  * Holds if `e` potentially overflows and `use` is an operand of `e` that is not guarded.
  */
 predicate missingGuardAgainstOverflow(Operation e, VariableAccess use) {
-  (
-    convertedExprMightOverflowPositively(e)
-    or
-    // Ensure that the predicate holds when range analysis cannot determine an upper bound
-    upperBound(e.getFullyConverted()) = exprMaxVal(e.getFullyConverted())
-  ) and
+  // Since `e` is guarenteed to be a `BinaryArithmeticOperation`, a `UnaryArithmeticOperation` or
+  // an `AssignArithmeticOperation` by the other constraints in this predicate, we know that
+  // `convertedExprMightOverflowPositively` will have a result even when `e` is not analyzable
+  // by `SimpleRangeAnalysis`.
+  convertedExprMightOverflowPositively(e) and
   use = e.getAnOperand() and
   exists(LocalScopeVariable v | use.getTarget() = v |
     // overflow possible if large
@@ -126,12 +125,11 @@ predicate missingGuardAgainstOverflow(Operation e, VariableAccess use) {
  * Holds if `e` potentially underflows and `use` is an operand of `e` that is not guarded.
  */
 predicate missingGuardAgainstUnderflow(Operation e, VariableAccess use) {
-  (
-    convertedExprMightOverflowNegatively(e)
-    or
-    // Ensure that the predicate holds when range analysis cannot determine a lower bound
-    lowerBound(e.getFullyConverted()) = exprMinVal(e.getFullyConverted())
-  ) and
+  // Since `e` is guarenteed to be a `BinaryArithmeticOperation`, a `UnaryArithmeticOperation` or
+  // an `AssignArithmeticOperation` by the other constraints in this predicate, we know that
+  // `convertedExprMightOverflowNegatively` will have a result even when `e` is not analyzable
+  // by `SimpleRangeAnalysis`.
+  convertedExprMightOverflowNegatively(e) and
   use = e.getAnOperand() and
   exists(LocalScopeVariable v | use.getTarget() = v |
     // underflow possible if use is left operand and small