Test files for negative chromaticity values

One uses the ACES AP0 primaries, with explicit negative value for blue y:

                 CIE x          CIE y
Red         0.7347        0.2653
Green     0.0              1.0
Blue        0.0001      –0.077
White     0.32168      0.33767

The other uses AP1 primaries, where x and y are positive but z = 1 - y - 
x is negative for red. Apps that calculate z using unsigned integers 
will get the wrong result.

                 CIE x          CIE y
Red         0.713       0.293
Green     0.165       0.830
Blue        0.128       0.044
White     0.32168      0.33767

-- 
Chris Lilley
@svgeesus@mastodon.scot
Technical Director @ W3C
W3C Technical Programming Team, Core Web Design