fix: fix remake for symbolic indexing, add tests for remake

[AayushSabharwal]

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[codecov]

Codecov Report

Attention: Patch coverage is 61.90476% with 24 lines in your changes are missing coverage. Please review.

Project coverage is 38.53%. Comparing base (21e7460) to head (30c96ab).
Report is 2 commits behind head on master.

Files	Patch %	Lines
src/remake.jl	61.90%	24 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #644      +/-   ##
==========================================
+ Coverage   37.54%   38.53%   +0.99%     
==========================================
  Files          55       55              
  Lines        4294     4287       -7     
==========================================
+ Hits         1612     1652      +40     
+ Misses       2682     2635      -47     

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[ChrisRackauckas]

It looks like a lot of tests are failing here?

[AayushSabharwal]

Hopefully this fixes them. There are a bunch of edge cases with remake