Currently, when Angular Material is loaded in an application that has
Trusted Types enforced, two violations occur. Both violations are caused
when a plain string is passed to angular.element since there is no
guarantee that the string was not derived from user input, which could
cause XSS. It should be noted that, in this case, neither call to
angular.element represents a security vulnerability, but this blocks
Trusted Types adoption in applications that load Angular Material.

To fix the violations, refactor the calls to angular.element to use safe
DOM operations instead.

This change does not alter any functionality and is fully backwards
compatible.

(cherry picked from commit 4e354a6)

- allow screen readers to do more and us to do less
  - remove extra calls to announce the item that is visually focused
  - remove tests for these extra live announcements
  - give every option an id for use with `aria-activedescendant`
  - use the `selected` class for styling and finding the active option
- implement recommendations from a11y guides
  - add the clear button to the tab order
  - change input type to `text`
  - always define a `name` attribute
- when the popup isn't expanded
  - `aria-owns` and `aria-activedescendant` shouldn't be defined
- when the autocomplete is disabled
  - `aria-autocomplete` and `aria-role` shouldn't be defined
  - `aria-haspopup` should be false
- add md-autocomplete-suggestion class for styling instead of using `li`
- add `md-autoselect` to the dialog demo for help w/ manual testing
- remove overly verbose `aria-describedby` from basic demo
- mark `md-icons` in `md-item-templates` of autocomplete demos as hidden
- update demos to use `md-escape-options="clear"` for better a11y

Fixes #11742

(cherry picked from commit 8c159aa)