refactor: simplify exponential backoff and refactor env

[withinboredom]

This steals the movement of the env functions from #1137 and refactors the exponential backoff logic, while greatly simplifying it.

The new exponential backoff api is quite simple:

• .wait(): pauses execution if there has been a crash
• .recordSuccess(): resets the backoff state
• .recordFailure(): increments the pause and returns true if we've crashed too many times

[dunglas]

Good refactoring!

[AlliBalliBaba]

As a sidenote, the segfault in the 8.3 tests also randomly happens on main, see #1141