add failing test for #13268
put the tooltips into the DOM in the tooltip unit tests
don't show tooltips/popovers whose element isn't in the DOM; fixes #13268
Merge pull request #13752 from twbs/fix-13268

Proposed fix for #13268
there is no need for this.offsets and this.targets to be jQuery objects
no need to check for href attribute on the scrollable element
removing this.$element as it is a superfluous copy of this.$scrollElement
refactor scrollspy refresh method

Closes #13702 by merging a rebased version of it.
Merge branch 'mikegreiling-scrollspy-update'