Previously there was a custom version of the testing app for Stackblitz that would run the tests in the browser.
With the web-container approach, this is no longer necessary since the tests can be run directly from the command line.
Fixes#44047
PR Close#44085
We should primarily point readers to the stackblitz that contains the spec files and runs them.
The application stackblitz is secondary (and doesn't actually contain the spec files, which is confusing).
Fixes#38535
PR Close#42406
- Update the `stackblitz.json` config files (used for generating
Stackblitz projects and ZIP archives) to include the correct files
(taking into account the current layout of the example projects).
- Update the boilerplate files for `testing` examples to match the
current layout of the example projects.
PR Close#31937
