Fix incorrect usage of S_FALSE which was used to indicate errors
although it is a HRESULT success code.
Make this function behave like the Windows 8 implementation and
the according MSDN specification.
- return E_INVALIDARG instead of S_FALSE if pszPath is NULL
- return E_INVALIDARG instead of S_FALSE if pszMore is NULL
- return E_INVALIDARG if cchPath is zero
- return E_INVALIDARG if cchPath is greater than PATHCCH_MAX_CCH
- return HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE) if the combined
path size exceeds cchPath (this is the same HRESULT which the Windows
implementation returns in this case and which is referred to as
PATHCCH_E_FILENAME_TOO_LONG on msdn)
Also extended/fixed the TestPathCchAppend ctest
178afd8dd5