Fixes some requests not being tracked in performance bar

Closes #57886

See merge request gitlab-org/gitlab-ce!25384

(cherry picked from commit 197641c7)

0e07a5aa Fixes some requests not being tracked in performance bar

Dimitrie Hoekstra authored 6 years ago and Dennis Tang committed 6 years ago

- Tooltips, by default, will display at the top of the element, instead
of at the bottom
- Note actions and emoji awards tooltips are now top-positioned

Wraps all imports for select 2 to deferred imports,
especially in the main.js we are actually checking if there 
is any select 2 element on the page or not.

In [!21565][0] we removed the loadCheck function from the LazyLoader for
images. The function seemed to be obsolete before anyhow, because we
make use of the MutationObserver in order to detect elements added /
removed from the DOM.

[0]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21565

From https://gitlab.com/gitlab-org/gitlab-ce/issues/36760

Was reverted in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14373