MAINT: Buttress memory handling in C csv engine

[gfyoung]

Title is self-explanatory.

Follow-up to #16663.

[codecov]

Codecov Report

Merging #16673 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #16673      +/-   ##
==========================================
+ Coverage   90.92%   90.95%   +0.02%     
==========================================
  Files         161      161              
  Lines       49272    49272              
==========================================
+ Hits        44803    44815      +12     
+ Misses       4469     4457      -12

Flag	Coverage Δ
#multiple	88.71% <ø> (+0.02%)	⬆️
#single	40.22% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/plotting/_converter.py	65.05% <0%> (+1.81%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0281886...86c5b9a. Read the comment docs.

[gfyoung]

@jreback : If #16675 works, then I'll close this PR in favor of that one.

[gfyoung]

Yep, #16675 is working. Closing this PR.