To break up the lab(), lch() change, it was opted to initially land with an explicit clamp to sRGB to avoid the subtle rounding issues we were seeing with CG. 

We should remove explicit clamp to SRGB by either:
- Explicit conversion to ExtendedSRGB (-Inf,Inf), which will avoid using CG's color conversion code, but won't be re-usable down the road if we want to use CG for things like gradients in the Lab color space.
- Passing the Lab color to CG and identifying and working around the precision issues in the tests.

Note: this is a test bug, please ignore :)