Code cleaning: Some iterating variables in builtin_functions.cpp can be const (#32852)
Summary:
To suppress a clang-tidy warning:
torch/csrc/jit/script/builtin_functions.cpp#L89
[performance-for-range-copy] warning: loop variable is copied but only
used as const reference; consider making it a const reference
Also make the const qualifier of scalar explicit.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32852
Differential Revision: D19663277
Pulled By: ezyang
fbshipit-source-id: f4ec5688d3cbea9a5f40db6063b7d111b0bf0cce
