adopt Ava default `files` glob

[erights]

Repeating https://github.com/Agoric/agoric-sdk/issues/8273

What is the Problem Being Solved?

Our package.json has an "ava": section that configures a custom "files" glob. There are two problems with this:

1. It requires that every package.json repeat the same custom config. Customizing tool defaults should have a high bar because of the maintenance cost they incur.
2. The naming scheme chosen puts "test" at the front of what is obviously a test from its path context. To run a particular test from the CLI requires typing "test" three time to pick one: yarn test test/test-something.js. With Ava's default it would be yarn test test/something.test.js and typing the "so" can autocomplete.

Description of the Design

Remove all the custom globs. Rename test files to .test.js.

Security Considerations

none

Scaling Considerations

none

Test Plan

CI

Upgrade Considerations

none

[erights]

This should only be fixed for endo (this issue) in coordination with fixing it for agoric-sdk (https://github.com/Agoric/agoric-sdk/issues/8273)

See https://github.com/Agoric/agoric-sdk/pull/8653#pullrequestreview-1795505142