C++: Add TConstantValueNumber case to ValueNumber::getKind

Author: MathiasVP

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/gvn/ValueNumbering.qll

@@ -58,6 +58,8 @@ class ValueNumber extends TValueNumber {
     or
     this instanceof TInitializeThisValueNumber and result = "InitializeThis"
     or
+    this instanceof TConstantValueNumber and result = "Constant"
+    or
     this instanceof TStringConstantValueNumber and result = "StringConstant"
     or
     this instanceof TFieldAddressValueNumber and result = "FieldAddress"