C++: use argumentCount in loops in initializer.

argumentCount is a more expensive function, so try to call it only once,
esp. in loops.

Change-Id: I6f0d420352743ec444487ce3f506ef28e5282d1e
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/libs/cplusplus/ResolveExpression.cpp

@@ -638,7 +638,7 @@ bool ResolveExpression::visit(CallAST *ast)
 
                 int score = 0;
 
-                for (unsigned i = 0; i < funTy->argumentCount(); ++i) {
+                for (unsigned i = 0, argc = funTy->argumentCount(); i < argc; ++i) {
                     const FullySpecifiedType formalTy = funTy->argumentAt(i)->type();
 
                     FullySpecifiedType actualTy;