_cogl_pipeline_progend_glsl_pre_change_notify and
_cogl_pipeline_progend_glsl_layer_pre_change_notify were only dirtying
the current program state for changes related to fragment processing.
This make both functions also check for changes that affect vertex
shader codegen.
This also fixes a mistake where
_cogl_pipeline_progend_glsl_layer_pre_change_notify was checking for
non-layer related changes which would never be seen, and instead it
should be checking for layer based changes only.
56ae6f9afa