Get bun test working locally

[thegedge]

What does this PR do and why?

Before this PR, bun test would have a ton of failures if you ran it locally. We didn't see this in CI because our runners would test each file separately from one another.

After doing some digging, I found a couple of issues:

1. AFAICT, bun test maintains globals across modules (unlike jest), so you have to be careful to reset it.
2. Sometimes tests would hang because failures wouldn't call the done callback.
3. Some other issue that I could not explain with this test:

   mobx-state-tree/__tests__/core/model.test.ts

   Lines 212 to 230 in fc60d76

   	test("it should show friendly message", () => {
   	const UserModel = types
   	.model("UserModel", {
   	id: types.identifier,
   	name: types.string
   	})
   	.views((user) => ({
   	get name() {
   	return user.name
   	}
   	}))
   	expect(() =>
   	UserModel.create({
   	id: "chakri",
   	name: "Subramanya Chakravarthy"
   	})
   	).toThrow("[mobx-state-tree] name property is declared twice")
   	})

And the various solutions:

1. Introducing a setup script that ensures we reset state before/after each test.
2. Switch to await / async vs callbacks.
3. Check for overlapping view/properties when instantiating the views vs discovering this issue when getting the atoms, which we were doing here:

   mobx-state-tree/src/types/complex-types/model.ts

   Lines 651 to 658 in fc60d76

   	try {
   	// TODO: FIXME, make sure the observable ref is used!
   	const atom = getAtom(node.storedValue, name)
   	;(atom as any).reportObserved()
   	} catch (e) {
   	throw new MstError(`${name} property is declared twice`)
   	}
   	res[name] = this.getChildNode(node, name).snapshot

Steps to validate locally

All of the following should succeed:

• bun test
• bun run test:dev
• bun run test:prod

[coolsoftwaretyler]

Ooh very exciting! Thanks for figuring this out! Will take a look soon.