[mlir] Remove SameOperandsAndResultShape when redundant with ElementwiseMappable

SameOperandsAndResultShape and ElementwiseMappable have similar
verification, but in general neither is strictly redundant with the
other.

Examples:
- SameOperandsAndResultShape allows
  `"foo"(%0) : tensor<2xf32> -> tensor<?xf32> but ElementwiseMappable
  does not.
- ElementwiseMappable allows
  `select %scalar_pred, %true_tensor, %false_tensor` but
  SameOperandsAndResultShape does not.

SameOperandsAndResultShape is redundant with ElementwiseMappable when
we can prove that the mixed scalar/non-scalar case cannot happen. In
those situations, `ElementwiseMappable & SameOperandsAndResultShape ==
ElementwiseMappable`:
- Ops with 1 operand: the case of mixed scalar and non-scalar operands
  cannot happen since there is only one operand.
- When SameTypeOperands is also present, the mixed scalar/non-scalar
  operand case cannot happen.

Differential Revision: https://reviews.llvm.org/D91396