Disable vendor formats for cl_ext_image_from_buffer tests, e.g: CL_NV21 from cl_img_yuv_image.

Hi,

Should we limit the cl_ext_image_from_buffer tests to only the core formats of the specification? In the same way the other image kernel_read_write do with `filter_formats`?

For format like YUV (E.g. CL_NV21_IMG), the verification step is incorrect.

Ahmed.

Locate the cl_ext_image_from_buffer tests and compare their format handling with the other image kernel_read_write tests that use filter_formats. Run the existing tests to reproduce the incorrect verification for formats such as CL_NV21_IMG; done means vendor formats are excluded while core specification formats remain covered.

Written by the indexing model from the issue text.