remove dead code in src/math

[araujoms]

I'm removing dead code from the repository, to improve maintainability and reduce invalidations. There are three categories that I'm removing here:

1. Code that simply copied the fallback methods from Base, and thus was causing unnecessary invalidations.
2. Code that wasn't exported or called from anywhere else in the package.
3. Code that was commented out.

There is also plenty of dead code in other folders, but I thought it would be better to restrict this PR to src/math because it's already quite large.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.22%. Comparing base (f00b992) to head (bae2843).
⚠️ Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #238      +/-   ##
==========================================
+ Coverage   49.26%   52.22%   +2.96%     
==========================================
  Files          63       58       -5     
  Lines        3400     3144     -256     
==========================================
- Hits         1675     1642      -33     
+ Misses       1725     1502     -223     

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[araujoms]

Any particularly reason this one wasn't merged?