global error tests should be rewritten as expect extentions

We have numerous instances of global.expect...
```
// eslint-disable-next-line jest/expect-expect
test('when path is not a valid string', async () => {
await global.expectToThrowBadArg(files.delete.bind(files, 123), ['filePath', 'string'], { filePath: 123, options: {} })
})
```
This means, we need to have many, many `eslint-disable-next-line jest/expect-expect`

A better practice, and the jest recommended way is to define our own expect extensions
```
expect.extend({
toThrowBadArg: ( words, options ) => {
// more expectations here ...
}
})

// then tests call it like this:
expect(files.delete.bind(files, 123)).toThrowBadArg( ['filePath', 'string'], { filePath: 123, options: {} })

```

If we do this well, they can be reused across multiple repo/libs

Locate the tests using global.expect and the repeated eslint-disable-next-line jest/expect-expect comments. Read the existing Jest test setup and the global error helpers first, then determine the shared expect extensions needed for the current error assertions. Done means the affected tests use the Jest extension style, retain their coverage, and no longer need those disables.

Written by the indexing model from the issue text.