[Prism] Add previousInput watermark and use it in bundleReady

[shunping]

A different approach of #36133.

addresses #36128

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.84%. Comparing base (2beb75c) to head (471708b).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #36137      +/-   ##
============================================
- Coverage     56.85%   56.84%   -0.01%     
  Complexity     3385     3385              
============================================
  Files          1220     1220              
  Lines        185400   185404       +4     
  Branches       3520     3520              
============================================
- Hits         105405   105401       -4     
- Misses        76658    76670      +12     
+ Partials       3337     3333       -4     

Flag	Coverage Δ
go	28.21% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[lostluck]

I think #36133 is what I was originally thinking of, but I much prefer this. It's inline with the other watermark tracking fields, and doesn't have a bit going back and forth, which gave me pause. We are checking a property of the watermarks with respect to the other data which is inline with the rest of the ready check.

#36128 (comment) is a good find, and this change satisfies the most important property: All the currently passing tests still pass!

Are there any additional tests we can enable that now pass? (no worries if nothing looks promising at this stage, I know there's additional work in progress that do need this case).

[shunping]

Are there any additional tests we can enable that now pass? (no worries if nothing looks promising at this stage, I know there's additional work in progress that do need this case).

We only change the timing when a bundle is claimed to be ready in certain circumstance. The window pane behavior is not changed in this PR. I am going to look into the extra window pane in the next one.

[github-actions]

Assigning reviewers:

R: @lostluck for label go.

Note: If you would like to opt out of this review, comment assign to next reviewer.

Available commands:

• stop reviewer notifications - opt out of the automated review tooling
• remind me after tests pass - tag the comment author after tests pass
• waiting on author - shift the attention set back to the author (any comment or push by the author will return the attention set to the reviewers)

The PR bot will only process comments in the main thread (not review comments).