Reverts "Make tests more resilient to Skia gold failures and refactor flutter_goldens for extensive technical debt removal" (#140085)

Reverts flutter/flutter#139549
Initiated by: Piinks
This change reverts the following previous change:
Original Description:
* Remove all use of global variables.
* Always pass in all dependencies, only create them in main or in tests.
* Pass in the "print" primitive.
* Make all network traffic retry (except when run locally, when it just auto-passes).
* Enable tests to be run in random order.