Fix and test reuse_symbolic=false for UMFPACK lu!()

[johnomotani]

The reuse_symbolic=false option for UMFPACK's lu!() is broken, due to undefined Tv and Ti. This PR fixes that bug, and adds a test that uses reuse_symbolic=false.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.40%. Comparing base (6de7bed) to head (5181f06).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #712      +/-   ##
==========================================
- Coverage   84.42%   84.40%   -0.03%     
==========================================
  Files          13       13              
  Lines        9400     9400              
==========================================
- Hits         7936     7934       -2     
- Misses       1464     1466       +2     

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[araujoms]

Instead of copy-pasting the entire test you could add another loop for reuse in (true, false).

[johnomotani]

Instead of copy-pasting the entire test you could add another loop for reuse in (true, false).

@araujoms - done.

[araujoms]

Thanks for your contribution!