core-image-sato-ptest-fast: Add 'fast' ptest execution image

core-image-sato-ptest-fast: Add 'fast' ptest execution image

Create a common include file which lists recipes that have ptests divided
into 'fast' and 'slow' groups. This allows us to include ptests which otherwise
may not get included in images and allows us to test the faster running things
more regularly.

The new image allows access to these faster executing tests. 'fast' is defined
as tests which execute in under 30s roughly speaking.

(From OE-Core rev: 2d8f8ab85d98929b0f1f699f256b40b1d9cddaec)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>