Exclude RGB565 blending cases from the must-pass

The verification logic of the groups below do not account for all the
possible valid results in the RGB565 output.

The change removes following in the group
dEQP-GLES3.functional.fragment_ops.blend.default_framebuffer
.rgb_func_alpha_func.*
.equation_src_func_dst_func.*

Bug: 23278613
Change-Id: Ic4cb194c1bf6326d7a12005ada12ab05c1ab669b
3 files changed