Enable copying of nested calldata dynamic arrays to storage in evmasm pipeline

[r0qs]

This is a follow-up PR suggested in #15984 (comment)

After the changes in #15984, the evmasm pipeline now supports copying nested calldata dynamic arrays to storage by utilizing existing Yul utility functions. Previously, the old assembly implementation could not handle such cases. In #15984, we intentionally maintained this limitation temporarily for backward compatibility.

[r0qs]

Note that, this test was restricted to via-IR only, but it would never actually be captured by the removed assertion. The test copies S[][] from memory to storage, but since the base type is an array, it enters the nested array check (i.e. if block) instead of the else block. And since it copies from memory (not calldata), the calldata-only assertion passes.

[r0qs]

Although #15984 refactored this part of the code, the behavior appears to predate those changes. The original code already had the same if-else structure that routes S[][] to the nested array check instead of the struct check for this specific case. See the original code here: https://github.com/argotorg/solidity/pull/15984/changes#diff-870828b8ab9a87c930141e3bde431c7976e1ef6c848cd2473a9cf018ab1e5ec8L184