CppLocatorFilter: Fix result sorting

* Fix rating items with startsWith()/contains() higher
* Rate matches in function parameter list lower

Task-number: QTCREATORBUG-19377
Change-Id: I2ea4c3ba96cd086aef82627326fa0888f700850f
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

tests/cpplocators/testdata_basic/file1.cpp

@@ -13,6 +13,7 @@ int myVariable;
 int myFunction(bool yesno, int number) {}
 
 struct Pos {};
+int somePositionWithin() { return 3; }
 void pointOfService() {}
 int matchArgument(Pos p) { return 0; }
 int positiveNumber() { return 2; }