[Nmock-general] Fix for the fix

[Jim A. <JA...@th...>]

Predictably, there was a bug in the patch I posted yesterday (types were
not reused if they had any unmockable methods).  Updated
MockTypeIdentifier.cs and tests attached.

Jim

(See attached file: MockTypeIdentifierTest.cs)(See attached file:
ClassGeneratorTest.cs)(See attached file: MockTypeIdentifier.cs)