Use dynamic import instead of require to load the incremental cache
handled, so when using ESM it will still work.

Updated the tests and merged them into new test suite, include 3 cases
of custom cache definition:
- CJS with `module.exports`
- CJS with `exports.default` with ESM mark
- ESM with `export default`

Closes NEXT-1924
Fixes vercel#58509

### Fixing a bug

### What?
Custom cache handler doesn't work on Windows

### Why?

It broke in a recent fix, when adding ESM support - #59863. The problem
is not new - dynamic imports consider an absolute path in Windows as a
protocol:

`ERR! Error [ERR_UNSUPPORTED_ESM_URL_SCHEME]: Only URLs with a scheme
in: file, data are supported by the default ESM loader. On Windows,
absolute paths must be valid file:// URLs. Received protocol 'C:'`

### How?

As a solution, it is necessary to explicitly indicate that it is indeed
an absolute path, for example by adding a / at the beginning, but the
most reliable way is to use pathToFileURL.

Since the logic is repeated in 4 places - I created a common function.

Fixes #58509

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Co-authored-by: JJ Kasper <jj@jjsweb.site>