🏗 Rewrite `gulp ava` using the `ava` CLI (ampproject#32602)

🏗 Clean up log coloring, enable on GH Actions (ampproject#32604)

Delete README.md (ampproject#32572)

This file is not needed. The parsing of this file is already implemented in html5dataset_test. The formatting of this file is different from original source to this repository blocking pull requests and manually prettifying on each update.

A version of whenContentLoaded without measurements (ampproject#32397)

* A version of whenContentLoaded without measurements

* fix tests

* review fixes

* Free up the experiment slot

* debugging

* restore

* reduce delta with pre-experiment code

Display-observer: a hidden tab should still be displayable for playba…

…ck (ampproject#32478)

* Display-observer: a hidden tab should still be displayable for playback

* review fixes

(cherry picked from commit 4a43478)

🔥 [amp-video] Don't update isPlaying if managed by stories (ampprojec…

…t#32355)

* draft

* ifManagedByPool

(cherry picked from commit 7ee9778)

Display-observer: a hidden tab should still be displayable for playba…

…ck (ampproject#32478)

* Display-observer: a hidden tab should still be displayable for playback

* review fixes

(cherry picked from commit 4a43478)

Display-observer: a hidden tab should still be displayable for playba…

…ck (ampproject#32478)

* Display-observer: a hidden tab should still be displayable for playback

* review fixes

(cherry picked from commit 4a43478)

✨[no-signing] Allow creatives to opt out of client side validation (a…

…mpproject#32446)

* fallback

* test

* dep-check

* dep check try 2

Launch layout-aspect-ratio-css to 10% (ampproject#32419)