Create test to ensure maxRenderCountEstimate is never being set to Infinity in virtual-list component in Fx View

Adding this as a follow-up to bug 1870141. We should add a test to make sure we don't fall into the same scenario in the future.

These were the original STR before the fix was added in bug 1870141:
With lots of open tabs (at least 100 or so), you can scroll down in the list so that it loads a few more of the sublists, then switch to another page in Fx View and then back to Open Tabs, and then you see the issue. When it returns to that page, it's initially getting 0 for the itemHeightEstimate (potentially due to changes from bug 1857634), and maxRenderCountEstimate is then being set to Infinity.

The test should recreate this scenario and make sure maxRenderCountEstimate is never being set to Infinity.

Kindly assign it to me :kcochrane, I'd love to get my hands dirty with this

can this be reassigned to me? it is over 24 hours already

submitted patch: https://phabricator.services.mozilla.com/D290420

https://phabricator.services.mozilla.com/D292793

There's no need to need info me or comment with the patch link. It automatically adds it to my review queue and adds it as an attachment in this bug.

Reverted this because it was causing mochitests failures in browser_firefoxview_virtual_list.js.

• Revert link
• Push with failures
• Failure Log
• Failure line: TEST-UNEXPECTED-FAIL | browser/components/firefoxview/tests/browser/browser_firefoxview_virtual_list.js | test_max_render_count_never_infinity - maxRenderCountEstimate should be finite when itemHeightEstimate is 0, got Infinity - false == true

https://hg.mozilla.org/mozilla-central/rev/cc2d48f6c50b