This MR: - adds tests for when MF_MT_AM_FORMAT_TYPE is missing or set to GUID_NULL; and - modifies MFCreateWaveFormatExFromMFMediaType to pass these tests
-- v3: mfplat: Allow MF_MT_USER_DATA to be missing for all subtypes. mfplat/tests: Add additional MFCreateWaveFormatExFromMFMediaType tests.