[mlir][linalg] Perform checks early in hoist padding.

Instead of checking for unexpected operations (any operation with a region except for scf::For and `padTensorOp` or operations with a memory effect) while cloning the packing loop nest perform the checks early. Update `dropNonIndexDependencies` to check for unexpected operations. Additionally, check all of these operations have index type operands only.

Depends On D114428

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D114438