fix: Updated Shim to properly calculate the _moduleRoot on windows environments

[bizob2828]

Description

This PR simplifies the calculation of this._moduleRoot on shim. Since require-in-the-middle has been introduced it passes us the module root as basedir which gets passed in as resolvedName. The previous logic traversed up directories to find the appropriate root. This logic did not account for windows paths in the regular expression. Instead of fixing that I found this code confusing and unnecessary. For built in packages, the this._moduleRoot will be set as .. this._moduleRoot is only used when calling shim.require which is only done in 3rd party instrumentation so setting builtins to . is really just defensive code.

The only issue I have with this PR is I cannot figure out how to create a failing test for the issue as it only exists on windows and I can't seem to affect path.dirname without using path.win32.dirname but that is not called in shim code.

How to Test

I have a vm that I can standup that shows my PR addresses the issue.

Related Issues

Closes #2012

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b460c7b) 97.07% compared to head (c2112ce) 97.07%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2014      +/-   ##
==========================================
- Coverage   97.07%   97.07%   -0.01%     
==========================================
  Files         225      225              
  Lines       40490    40487       -3     
==========================================
- Hits        39307    39304       -3     
  Misses       1183     1183              

Flag	Coverage Δ
integration-tests-16.x	78.80% <100.00%> (-0.03%)	⬇️
integration-tests-18.x	79.07% <100.00%> (-0.03%)	⬇️
integration-tests-20.x	79.07% <100.00%> (-0.04%)	⬇️
unit-tests-16.x	91.05% <100.00%> (-0.01%)	⬇️
unit-tests-18.x	91.03% <100.00%> (-0.01%)	⬇️
unit-tests-20.x	91.03% <100.00%> (-0.01%)	⬇️
versioned-tests-16.x	74.63% <100.00%> (-0.03%)	⬇️
versioned-tests-18.x	74.65% <100.00%> (-0.03%)	⬇️
versioned-tests-20.x	74.66% <100.00%> (-0.03%)	⬇️

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[sumitsuthar]

module.isBuiltin() API was added in Node.js v16.17.0 What about the versions below v16.17.0?
https://nodejs.org/docs/latest-v16.x/api/module.html#moduleisbuiltinmodulename

[jsumners-nr]

We support all current LTS releases as described at https://docs.newrelic.com/docs/apm/agents/nodejs-agent/getting-started/compatibility-requirements-nodejs-agent/#system

[bizob2828]

Yea we're a little delayed on dropping 16. This was because it was dropped out of band from their normal LTS schedule