build: Update qunitjs to 2.9.1

build: Update qunitjs to 2.9.1

Code and integrity from <https://code.jquery.com/qunit/>.
Release notes at <https://github.com/qunitjs/qunit/releases>.

Highlights for the browser version:

- [2.7.0] Reporter: Remove cost of DOM size when
  using "hidepassed=true".
- [2.7.0] Reporter: Use perf.now() for improved accurracy
  of unit test durations.
- [2.7.0] Reporter: Make debugging tests in a browser
  easier by adding timeline markers for DevTools.

Highlights for the npm package / CLI version:

- [2.9.0] CLI: Reduce dependency tree size
               from 143 packages to 9 packages.

Change-Id: I38408d90765cd18d5dd6952b8b6b30cbfa0c7ed5