ole32: Check that the storage was opened with write access before creating a new stream or sub-storage.

Copy the mode flags into the STATSTG structure in IStorage::Stat. Don't 
store the STGM_CREATE flag in openFlags, since it is only relevant when 
opening the stream and the tests show that it isn't returned in the 
STATSTG structure.

Check the access mode for opening and creating streams and storages
doesn't exceed the access rights the current storage was opened with,
not the parent storage.

Add more tracing for read and write operations and warn in the case of
failure.

Replace a test that fails on NT and with DCOM95 DLLs with a test that
ensures access permissions are checked correctly for sub-storages and
creating streams.

had their parent storage released.

For NtQueryInformationToken(TokenGroups), don't do a size check before
the server call, as we don't know how many SIDs there are to return
and hence the needed buffer size.

oleaut32: Split out the SAFEARRAY and BSTR tests so that they can be used in the upcoming VARIANT tests.