This commit fixes problem with loading N-API modules that use
the "old" way of registration (using "napi_module_register" API).
The slot was not cleared after loading modules, causing subsequent
calls that use the new way of registration (using
"napi_register_module_v1" API) to try and load the previous module.
Ref https://github.com/denoland/deno/issues/16460
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Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
