make_zero(!) bugfixes and improved tests

[danielwe]

Since #1852 isn't quite ready, in the meantime, here's a PR fixing the bugs I found in make_zero(!) and adding a fairly thorough test suite.

The last test currently fails due to #1935. I didn't want to mark it as broken because I'd rather see #1936 merged (or #1935 fixed in some other way), but let me know if I should change that.

[danielwe]

Thanks for taking a look! I noticed a few other issues that should be fixed too. However, #1852 is almost there (I've been in a cycle of thorough tests => noticing issues => fixing/improving design accordingly => repeat), so if you don't mind I'll finish the big push on that, and then we can decide whether it's worth fixing and merging this one first (say, if reviewing #1852 is too big of a task to deal with right now), or if we should close this one and focus on #1852

[vchuravy]

Can you rebase this? I think I would like to get this merged first before dealing with the much larger change in #1852

[danielwe]

Sure! Just give me a minute to incorporate some additional fixes and improvements I've made in the meantime

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.11888% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.64%. Comparing base (037dfed) to head (636b025).
⚠️ Report is 775 commits behind head on main.

Files with missing lines	Patch %	Lines
src/make_zero.jl	77.68%	27 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1961      +/-   ##
==========================================
+ Coverage   67.50%   70.64%   +3.14%     
==========================================
  Files          31       44      +13     
  Lines       12668    16122    +3454     
==========================================
+ Hits         8552    11390    +2838     
- Misses       4116     4732     +616     

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