[mlir] verify that operand/result_segment_sizes attributes have i32 element

This is an assumption that is made in numerous places in the code. In
particular, in the code generated by mlir-tblgen for operand/result accessors
in ops with attr-sized operand or result lists. Make sure to verify this
assumption.

Note that the operation traits are verified before running the custom op
verifier, which can expect the trait verifier to have passed, but some traits
may be verified before the AttrSizedOperand/ResultTrait and should not make
such assumptions.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D99183