[Attributor] AAValueConstantRange: Value range analysis using constant range

This patch introduces `AAValueConstantRange`, which answers a possible range for integer value in a specific program point.
One of the motivations is propagating existing `range` metadata. (I think we need to change the situation that `range` metadata cannot be put to Argument).

The state is a tuple of `ConstantRange` and it is initialized to (known, assumed) = ([-∞, +∞], empty).

Currently, AAValueConstantRange is created when AAValueSimplify cannot
simplify the value.

Supported
 - BinaryOperator(add, sub, ...)
 - CmpInst(icmp eq, ...)
 - !range metadata

`AAValueConstantRange` is not intended to extend to polyhedral range value analysis.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D71620