fix: support register measurement and loop-scoped registers

[rmshaffer]

Issue #, if available:

Description of changes:
Sits on top of #399. Additional changes necessary to support register measurement and loop-scoped registers which allows all tests & notebooks in amazon-braket/autoqasm#119 to pass successfully.

Testing done:

Merge Checklist

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (0972751) to head (f9e8723).

Additional details and impacted files

@@                Coverage Diff                 @@
##           output-simulator      #401   +/-   ##
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  Coverage            100.00%   100.00%           
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  Files                    50        50           
  Lines                  5164      5186   +22     
  Branches                625       631    +6     
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+ Hits                   5164      5186   +22     

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