You must have a wide-color-gamut compatible monitor in order for the test to even be possible. Most laptops and desktops do not.
Safari on my iPhone X passes.
Safari on my iPhone X passes.
This also ignores the shortcuts that Chrome and other browsers have taken on their road to colour management.
Maybe surprising to some, but Windows actually supports HDR10 (which includes "wide-gamut" color) better than other OSes. You can, for example, play HDR10 video games with a connected HDR-capable monitor. It might be thanks to MS's Xbox platform.