Allow negative Register reset values

[PrajwalVandana]

Pass bitwidth to infer_val_and_bitwidth in Register.init to allow negative Register reset values

[fdxmw]

Thank you for your contribution! This change looks good to me, but you'll need to fix the test failures before we can merge it. Please also add a test for the new behavior so we can make sure it doesn't regress. Thanks again!

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 91.9%. Comparing base (7b8d86a) to head (ed6caa6).
Report is 6 commits behind head on development.

Files with missing lines	Patch %	Lines
pyrtl/helperfuncs.py	80.0%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           development    #464     +/-   ##
=============================================
- Coverage         91.9%   91.9%   -0.0%     
=============================================
  Files               24      24             
  Lines             6417    6417             
=============================================
- Hits              5893    5892      -1     
- Misses             524     525      +1     

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[fdxmw]

Thank you for your patience, we are almost there, these should be my last comments :)

There are also a couple pycodestyle errors on this pull request that will need to be fixed:
pyrtl/helperfuncs.py:807:101: E501 line too long (103 > 100 characters)
pyrtl/helperfuncs.py:808:25: E131 continuation line unaligned for hanging indent