Reordering of custom attributes in the test assertions

This is necessary because we assert the order of method custom attributes (e.g. asserted IL code in ApprovedTests) although the order of custom attributes is not specified (see http://stackoverflow.comquestions/480007). Mono Cecil preserves the order.

Otherwise the `ApprovedTests.SpecialClass` and `SpecialClassNoAssert` fails on my system (VS 2013).