[WIP] Parallel Behavior Support

[Eric-Vin]

Description

Adds support for parallel behaviors.

Issue Link

N/A

Checklist

• I have tested the changes locally via pytest and/or other means
• I have added or updated relevant documentation
• I have autoformatted the code with black and isort
• I have added test cases (if applicable)

Additional Notes

N/A

[codecov]

Codecov Report

❌ Patch coverage is 35.78947% with 61 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.91%. Comparing base (4be87bd) to head (28f7c77).

Files with missing lines	Patch %	Lines
src/scenic/core/serialization.py	6.15%	61 Missing ⚠️

❌ Your patch check has failed because the patch coverage (35.78%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #472      +/-   ##
==========================================
- Coverage   89.85%   87.91%   -1.94%     
==========================================
  Files          48       48              
  Lines       13346    13431      +85     
==========================================
- Hits        11992    11808     -184     
- Misses       1354     1623     +269     

Files with missing lines	Coverage Δ
src/scenic/core/dynamics/behaviors.py	96.22% <100.00%> (+0.39%)	⬆️
src/scenic/core/simulators.py	83.86% <100.00%> (-11.99%)	⬇️
src/scenic/syntax/compiler.py	98.15% <100.00%> (-0.13%)	⬇️
src/scenic/core/serialization.py	34.79% <6.15%> (-56.55%)	⬇️

... and 11 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.