[IR] Lift attribute handling for assume bundles into CallBase

Rather than special-casing assume in BasicAA getModRefBehavior(),
do this one level higher, in the attribute handling of CallBase.

For assumes with operand bundles, the inaccessiblememonly attribute
applies regardless of operand bundles.

GitOrigin-RevId: 93a636d9f6385543a1c77506880a08e10c50792f
3 files changed