CDBurnerXP expects the ContextMenuHandlers key to exist, and apparently
enumerates it until it receives ERROR_NO_MORE_ITEMS. If it fails to open the
key, it will spin forever trying to call RegEnumKeyExW(NULL) and getting
ERROR_INVALID_HANDLE.

We could simply create an empty ContextMenuHandlers key here, but this will
allow the New menu to work in the builtin explorer view once shellex handlers
are implemented.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=29523

And add some tests.

Preparation for supporting setting TempoParam on tempotracks.

Much like we do in shader_spirv_find_graphics_program_variant_vk() for
shader_spirv_compile_shader(). When compiling an Aon9 shader,
"shader->byte_code" points to the DXBC container, while
"shader->function" points to the contained d3dbc shader.

This enables advanced color conversion in all cases, and thus allows
NV12 -> RGB32 conversion even when MF_SOURCE_READER_ENABLE_ADVANCED_VIDEO_PROCESSING
is not set. This should be harmless and makes the code simpler as we
can simply append a VideoProcessor transform in all cases.

The tests todos is tweaked to reflect cases where a single processor
is used, which outputs slightly different attributes to when it is
connected to an upstream decoder. Ultimately we could try to match
native here, but it shouldn't matter too much in the meantime.

To avoid conflict with handle mapping macros.