DomEvent functions not covered by tests

We have some DomEvent tests here: https://github.com/Leaflet/Leaflet/blob/master/spec/suites/dom/DomEventSpec.js, but not all functions are covered.

Here the list of lacking tests:

1. on(<HTMLElement> el, <String> types, <Function> fn, <Object> context?) (where types has several events)
2. on(<HTMLElement> el, <Object> eventMap, <Object> context?)
3. off(<HTMLElement> el, <String> types, <Function> fn, <Object> context?) (where types has several events)
4. off(<HTMLElement> el, <Object> eventMap, <Object> context?)

Note: some on/off tests implemented in #7125.

1. stop(<DOMEvent> ev)
2. getMousePosition(<DOMEvent> ev, <HTMLElement> container?)
3. getWheelDelta(<DOMEvent> ev)

Ref: https://leafletjs.com/reference-1.7.1.html#domevent

Note: When implementing required test cases consider minor refactoring in #7438 (which already has tests for disableScrollPropagation and disableClickPropagation).

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Related:

• DomEvent.DoubleTap.js is covered by #7027.
• DomEvent.Pointer.js is covered by #7415.

[johnd0e]

See also #7126.

[Crimson-riot]

Ok, #7453 is up and based on #7438 but it seems like I cannot link that PR to this issue