BLD/PERF: add missing noexcept qualifiers to Cython functions already declared as nogil

[neutrinoceros]

PR Summary

Since I'm spending a lot of time looking at wheels build logs I noticed we had a handful of warnings similar to:

performance hint: yt/geometry/grid_visitors.pyx:20:0: Exception check on 'free_tuples' will always require the GIL to be acquired.
Possible solutions:
	1. Declare 'free_tuples' as 'noexcept' if you control the definition and you're sure you don't want the function to raise exceptions.
	2. Use an 'int' return type on 'free_tuples' to allow an error code to be returned.

This fixes these. Some performance improvement is also excepted as a result, though I do not know of a realistic benchmark I could use to quantify it.

PR Checklist

• New features are documented, with docstrings and narrative docs
• Adds a test for any bugs fixed. Adds tests for new features.