Assert more invariants on ValueRanges (#94906)
The main new invariant is lower/upper must be a Sympy expression of some sort (filtered through `simple_sympify`). There are some simpler sanity checks (mostly making sure the range is well formed). There is a type confusion problem (it's not immediately obvious if a range is for float/int/bool) but we aren't going to solve this for now as it is more complicated.
Billing of changes:
* ValueRanges.wrap() now accepts sympy expressions
* ValueRanges now accepts non-sympy expressions and will sympyify them appropriately. Rewrite calls to ValueRanges to not sympify manually as it is unnecessary
* Don't attempt to test sqrt(-1)
* Add ValuesRanges.unknown() which gives -oo, oo bounds, and rewrite direct calls to -math.inf, math.inf to use it
* Make multiply work between ValueRanges.unknown() and ValueRanges.wrap(0)
* Consistently use sympy.oo instead of math.inf
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94906
Approved by: https://github.com/eellison
