ValueFlow: avoid unnecessary Value copies (#4835)

Author: firewave

lib/token.cpp

@@ -2154,7 +2154,8 @@ bool Token::addValue(const ValueFlow::Value &value)
         ValueFlow::Value v(value);
         if (v.varId == 0)
             v.varId = mImpl->mVarId;
-        mImpl->mValues = new std::list<ValueFlow::Value>(1, v);
+        mImpl->mValues = new std::list<ValueFlow::Value>;
+        mImpl->mValues->push_back(std::move(v));
     }
 
     removeContradictions(*mImpl->mValues);