Remove internal CE API usage from tests

[dvoytenko]

Partial for #31915.

This only affects tests. No code changes. Most of changes are replacing x.implementation_ with await x.getImpl().

However, there's an important purpose for this change: the tests no longer rely here on the implementation being immediately available when a DOM element is created. This is a big downpayment for the remainder of the refactoring.

[amp-owners-bot]

Hey @alanorozco! These files were changed:

extensions/amp-3q-player/0.1/test/test-amp-3q-player.js
extensions/amp-brid-player/0.1/test/test-amp-brid-player.js
extensions/amp-connatix-player/0.1/test/test-amp-connatix-player.js
extensions/amp-delight-player/0.1/test/test-amp-delight-player.js
extensions/amp-nexxtv-player/0.1/test/test-amp-nexxtv-player.js
extensions/amp-o2-player/0.1/test/test-amp-o2-player.js
extensions/amp-powr-player/0.1/test/test-amp-powr-player.js
extensions/amp-viqeo-player/0.1/test/test-amp-viqeo-player.js

Hey @gmajoulet, @newmuis, @Enriqe! These files were changed:

extensions/amp-story/1.0/test/test-amp-story.js

[samouri]

so many lines!