* refactor: simply browserslists defaults overwriting
When `hasTargets` is `false`, `targets` is always an empty object by definition, `objectToBrowserslist({})` always return `[]` therefore we can remove `objectToBrowserslist`.
* test: apply external-helpers on preset-env test fixtures
* test: add ie 6 to force all transforms in corejs 3, debug, corejs 2 fixtures
* Add ie 6 as targets for test fixtures
* fix: [#10561] _interopRequireWildcard should cache object only
* fix: narrow down cache restriction to object/function type
* test: add interop require null module case
* Improves the logic to import objects in helpers
* Modified to work with more cases.
* Modified by considering exception cases
* Fixed not using bundler's polyfill
Co-Authored-By: Jordan Harband <ljharb@gmail.com>
* Updated test output files
* Changes to cache logic
* Modified to use if statement
