Test proving Actors.Next unaffected by reentrancy bug

[WhitWaldo]

Description

Adding a test to prove that reentrant invocation on the same activation works in Actors.Next - related to #1908

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #[issue number]

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.06%. Comparing base (a7c0612) to head (c21f035).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1911      +/-   ##
==========================================
- Coverage   64.07%   64.06%   -0.01%     
==========================================
  Files         358      358              
  Lines       10485    10485              
  Branches     1246     1246              
==========================================
- Hits         6718     6717       -1     
- Misses       3430     3431       +1     
  Partials      337      337              

Flag	Coverage Δ
net10.0	64.02% <ø> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 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.