[mlir] Remove `Transforms/SideEffectUtils.h` and move the methods into...

[mlir] Remove `Transforms/SideEffectUtils.h` and move the methods into `Interface/SideEffectInterfaces.h`.

The methods in `SideEffectUtils.h` (and their implementations in
`SideEffectUtils.cpp`) seem to have similar intent to methods already
existing in `SideEffectInterfaces.h`. Move the decleration (and
implementation) from `SideEffectUtils.h` (and `SideEffectUtils.cpp`)
into `SideEffectInterfaces.h` (and `SideEffectInterface.cpp`).

Also drop the `SideEffectInterface::hasNoEffect` method in favor of
`mlir::isMemoryEffectFree` which actually recurses into the operation
instead of just relying on the `hasRecursiveMemoryEffectTrait`
exclusively.

Differential Revision: https://reviews.llvm.org/D137857