Extend offline-compression context

When using offline compression, all context information needs to be
available in order to generate matching compressor output.

Change I84807f6ca0d9769d25b942c151c1a83501648a0a introduced references
to HORIZON_CONFIG, so add it to the predefined list of context for
offline compression as well.

Change-Id: I44ee139626f0eac6fa34f9136926a1a626498039
Merge "Extend offline-compression context"