n-api: add more `int64_t` tests

* Updated tests for `Number` and `int32_t`
* Added new tests for `int64_t`
* Updated N-API `int64_t` behavior to return zero for all non-finite
  numbers
* Clarified the documentation for these calls.

Backport-PR-URL: https://github.com/nodejs/node/pull/19447
PR-URL: https://github.com/nodejs/node/pull/19402
Refs: https://github.com/nodejs/node-chakracore/pull/500


Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>