convert Chain Upgrade Tester to use JS instead of Bash

[turadg]

What is the Problem Being Solved?

https://github.com/Agoric/agoric-sdk/tree/master/packages/deployment/upgrade-test has become essential for testing pending chain upgrades. As the amount of code grows, we need to be able to refactor it. As the number of people using it grows, we need to be able to quickly explore dependencies and how it works.

Description of the Design

JavaScript provides refactoring and navigation tools that Bash lacks. Convert the Bash scripts to use JavaScript.

Maybe TypeScript because the type soundness is irrelevant for testing scripts.

TBD what runner to use. Some options:

• zx (example)
• zx markdown (motivation)
• execa $ helper
• our own version of $ (sample)

Security Considerations

Scaling Considerations

Test Plan

Testing tool. Requires some usability testing with developers before landing.

Upgrade Considerations