Bug 238543

As documented here: https://compat.spec.whatwg.org/#touch-action, "When specified, the pinch-zoom token enables multi-finger panning and zooming of the page.". And this implies that if pinch-zoom is not specified, then multi finger gestures should NOT pan the page. However, on Safari it appears they do.

Steps to reproduce:
1. Go to https://huijing.github.io/touch-action/ and look at the element with touch-action: pan-x (this is also relevant to touch-action: pan-y or touch-action: pan-x pan-y, though that example page doesn't have that latter example)
2. With two fingers, attempt to pan the element

Expected: No panning occurs
Action: Panning happens

For comparison, on Chrome on Android, multi finger panning is blocked when pinch-zoom isn't specified. See https://bugs.chromium.org/p/chromium/issues/detail?id=632525.