Benchmarks and IO fix

[kirillgarbar]

Proposed Changes

RAM consumption for loading matrices has been reduced several times.
Benchmarks on CI were not working due to NVIDIA set in config :)
Script is fixed, CI benchmarks at least work locally.

Types of changes

What types of changes does your code introduce to GraphBLAS-sharp?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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• Build and tests pass locally
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added necessary documentation (if appropriate)

Further comments

[gsvgit]

Что-то таки с путями не то: https://github.com/YaccConstructor/GraphBLAS-sharp/actions/runs/6767965616/job/18391500043