Fix feature support queries with mobileToDesktop

[steverep]

Fixes #761 by adding support for mobileToDesktop to feature queries.

• Changed the feature cache to a 2 dimensional object for each browser and version to make the implementation much simpler
• Uses existing function to get the mobile to desktop data
• Only looks to the desktop version's support data when (a) there is no mobile data and (b) the feature is supported by the latest mobile version
• Added a couple specific mobile to desktop tests and made the others more specific for the common data

Note the way the existing tests were messing with the cache property doesn't really work. This is evident if you just try to use the same feature from one test to the next (the first cache setting is always used). I didn't bother to try to make it work because I think it would involve exporting the cache itself, so I just removed some of that and use a different feature for each test.

[Semigradsky]

Just a reminder that need to change typings also:

browserslist/index.d.ts

Lines 125 to 129 in 312d763

	let cache: {
	[feature: string]: {
	[name: string]: 'y' | 'n'
	}
	}

[steverep]

Done. I changed the type to just string as there are more possibilities than just "y" or "n".

[ai]

Thanks! Released at 4.21.8.