Port the bitstruct packed array bug fix to master branch

[ptpan]

Back-port #248 to the master branch to unblock the C2S2 team.

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (b35d76e) 89.13% compared to head (4e7bd7b) 89.18%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #249      +/-   ##
==========================================
+ Coverage   89.13%   89.18%   +0.04%     
==========================================
  Files         329      330       +1     
  Lines       30302    30440     +138     
==========================================
+ Hits        27009    27147     +138     
  Misses       3293     3293              

Files	Coverage Δ
pymtl3/passes/sim/test/DynamicSchedulePass_test.py	96.89% <100.00%> (+1.53%)	⬆️
pymtl3/version.py	0.00% <0.00%> (ø)
pymtl3/dsl/Connectable.py	83.46% <55.55%> (-0.86%)	⬇️

... and 2 files with indirect coverage changes

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