Code quality improvements from isVisible refactor

[straker]

From #3351, listing changes we can make to improve the code that we didn't want to make in the large pr

• lib/checks/keyboard/accesskeys-evaluate.js - isVisibleOnScreen does not need to be used to determine if label is visible (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/checks/label/multiple-label-evaluate.js - based on the comment, !isHiddenForEveryone may be more appropriate than isVisibleOnScreen (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/commons/dom/get-rect-stack.js - may not need need width/height check if isVisibleOnScreen already does that (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/checks/shared/is-on-screen-evaluate.js - may not need isOffScreen as isVisibleOnScreen already checks for that (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/rules/is-visible-matches.js - file name is different than matches function name (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/rules/is-visible-matches.js - deprecate and replace with is-visible-on-screen-matches (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/rules/landmark-unique-matches.js - remove isVisibleForScreenreader call as it may not be useful (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/commons/dom/visiblity-methods.js - add tests for the functions when we can build the tests to allow ES6 imports (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))
• lib/core/core.js - move all uses of axe.__thisWillBeDeletedDoNotUse to its own file (feat: deprecate and replace dom.isVisible, utils.isHidden, and dom.isHiddenWithCss #3351 (comment))

[straker]

lib/commons/dom/get-rect-stack.js - may not need need width/height check if isVisibleOnScreen already does that (#3351 (comment))

The visibility methods do not look at the elements width/height. So the following DOM returns true for isVisibleOnScreen, so it is needed in get-rect-stack

<div style="width: 0; height: 0; padding: 0; margin: 0></div>

[straker]

lib/rules/landmark-unique-matches.js - remove isVisibleForScreenreader call as it may not be useful (#3351 (comment))

This fails a test in landmark-unique-matches for the test should not match because landmark is hidden which sets the landmark to display: none and expects the matcher to fail.

[straker]

All work completed