fixes another cause of #2497

[jurgenvinju]

This PR does some clean up that helps in debugging; making sure some assumptions about the contents of environments are true: some old code is removed that might break those assumptions, but it doesn't currently because it is never used.

The one change in the test code makes sure getRoot is called less often, which avoids running into the issue at hand, but doesn't solve it per se.

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 47%. Comparing base (934a820) to head (ae56fe4).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
src/org/rascalmpl/interpreter/env/Environment.java	0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2511   +/-   ##
=======================================
  Coverage       47%     47%           
+ Complexity    6708    6707    -1     
=======================================
  Files          791     791           
  Lines        65187   65160   -27     
  Branches      9751    9751           
=======================================
+ Hits         30925   30927    +2     
+ Misses       31849   31820   -29     
  Partials      2413    2413           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[jurgenvinju]

I think it this is a pure refactoring with no impact on runtime semantics in the Rascal project.

• The removed code was dead;
• env.getStore() is a faster short-hand for env.getRoot().getStore()ifenvis aModuleEnvironment`. A fast-path optimization by receiver specialization.
• Made all protected fields private in ModuleEnvironment without compilation issues.

Because we remove shallow cloning as a feature from ModuleEnvironment this increases the strength of our theory that only one ModuleEnvironment is present in memory for every module at a specific moment in time. This helps in the analysis of watch/reload, as well as the semantics of extend.