Add more tests for specific arguments passed to IHttpNegotiate and IHttpNegotiate2. Note that
for OnResponse pszAdditionalHeaders is NULL when called directly from IInternetProtocol (for
example as seen in our protocol tests) but non-NULL when these interfaces are exposed by
IBindStatusCallback as seen here. Tests conform on Win98 and Winxp.

urlmon: Add a reference to the IUnknown for Release of STGMEDIUM to account for extra call to ReleaseBindInfo.

Bytes can still be read with E_PENDING returned if the whole request could not be satisfied, don't
ignore those.