write a test for running two precompiled browser tests

[jakemac53]

This was intended as a regression test for #2294 but it actually passes 😭

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:fake_async	1.3.2	ready to publish	fake_async-v1.3.2
package:checks	0.3.1-wip	WIP (no publish necessary)
package:test	1.25.9-wip	WIP (no publish necessary)
package:test_api	0.7.4-wip	WIP (no publish necessary)
package:test_core	0.6.6-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[github-actions]

PR Health

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.