Selector: Re-expose jQuery.find.tokenize (3.x version)

Selector: Re-expose jQuery.find.tokenize (3.x version)

`Sizzle.tokenize` is an internal Sizzle API, but exposed. As a result,
it has historically been available in jQuery via `jQuery.find.tokenize`.
That got dropped during Sizzle removal; this change restores the API.

In addition to that, Sizzle tests have been backported for the following
APIs:
* `jQuery.find.matchesSelector`
* `jQuery.find.matches`
* `jQuery.find.compile`
* `jQuery.find.select`

A new test was also added for `jQuery.find.tokenize` - even Sizzle was
missing one.

Fixes gh-5259
Closes gh-5260
Ref gh-5263
Ref jquery/sizzle#242
Ref gh-5113
Ref gh-4395
Ref gh-4406