[MONDRIAN-1766]  Role restrictions are not honored in some cases if the number of MemberGrants exceeds the maxconstraints property value

This change introduces a final pass filter of the tuple list generated by NativeSet to assure that all items in the list are accessible.  Since this could be costly,
it short-circuits the checks except where one or more hierarchies actually have a role restriction defined.
[MONDRIAN-1766]  Code cleanup.  Inlined conditional.
Merge pull request #168 from mkambol/mondrian-1766

[MONDRIAN-1766]  Role restrictions are not honored in some cases if the number of MemberGrants exceeds the maxconstraints property value