Prefer bound_sympy over sympy_interp (#105138)
This is the first PR towards simplifying sympy_interp, and more
generally, simplifying the implementation of ValueRangeAnalysis for
SymPy expressions.
In general, it would be conteptually good to have a minimal subset of
operations that conform our SymPy expressions, let that be guards or
indexing expressions. This would allow us to reason better about SymPy
guards and potentially have invariants like knowing that guards are
continuous piecewise rational functions. If this were the case,
we could operate on them using exact arithmetic and completely avoid
precision errors like the one found in https://github.com/pytorch/pytorch/issues/105097
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105138
Approved by: https://github.com/ezyang
