Update the check-exact infrastructure to match ghc-exactprint

GHC tests the exact print annotations using the contents of utils/check-exact.

The same functionality is provided via https://github.com/alanz/ghc-exactprint

The latter was updated to ensure it works with all of the files on hackage when 9.2 was released, as well as updated to ensure users of the library could work properly (apply-refact, retrie, etc).

This commit brings the changes from ghc-exactprint into GHC/utils/check-exact, adapting for the changes to master.

Once it lands, it will form the basis for the 9.4 version of ghc-exactprint.

See also discussion around this process at #21355