This renames the global ctx and fb variables to test_ctx and test_fb
respectively in line with the names use on the master branch. This is to
make it easier to cherry pick patches from master.
The test creates a pipeline with two layers which add two different
color constants together and then tries various combinations of
removing the layers and checks that it gets the right color.
Currently this is failing if a pipeline is copied and then a layer is
removed from the copy.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 844440a5cee5907c4d61e995804534ac0613bb0f)
