If the inherited properties define a non-auto color, then
a specified COL_AUTO needs to be returned in order to
override the inherited color.

This affects three areas. Character fill, Paragraph fill,
and table cell fill. The unit tests cover all three areas.

This patch depends on the commits for tdf#91292

Change-Id: I1a043d2224b164c6c411ce2e46d899212f2b7f3d
Reviewed-on: https://gerrit.libreoffice.org/59313
Tested-by: Jenkins
Reviewed-by: Justin Luth <justin_luth@sil.org>