Based on a patch by Thomas Kho.

ole32: Add a test for the failure case of same-apartment unmarshaling when passing in an unsupported iid.

ole32: ReadClassStm should return STG_E_READFAULT is not all of the data could be read, not S_FALSE.

Clear pclsid in case of errors.
Add tests for ReadClassStm.

ole32: Add tests for invalid arguments of CoMarshalInterface and CoMarshalInterThreadInterfaceInStream.

ole32: Fix HGLOBALStreamImpl_CopyTo to check the return values of IStream_Read and IStream_Write and to not compare the bytes read to the bytes written.

Add tests for IStream::CopyTo of the HGLOBAL stream implementation.

Change some incorrect usages of SEEK_SET to the intended STREAM_SEEK_SET 
instead.