[Draft][FFI] Remove backwards-compatibility unwrapping of IntImm

[Lunderberg]

This is a follow-up PR to https://github.com/apache/tvm/pull/16183, which updated the FFI with explicit integer types. As part of that change, many internal functions were updated to accept non-IR types (e.g. Array<runtime::Int> instead of Array<IntImm>). For backwards compatibility with callees that provided the IR types, a specialization of PackedFuncValueConverter unwrapped the IntImm into a runtime::Int.

This commit removes the backwards-compatibility specialization of PackedFuncValueConverter. Breakages that are found in CI as a result will then be updated at the caller side, removing the need for the backwards-compatibility handler altogether.

[Lunderberg]

The initial commit in this PR branch only removes the backwards-compatibility handler, and does not yet update any callers. This is expected to trigger breakage in CI, which will identify the callers that must be updated.

[tqchen]

would be great to followup on this one

[Lunderberg]

Agreed, though unfortunately I haven't had time to do so. It looks like the current failures are in the relay/collage C++ testing, but I haven't looking into it.

[tqchen]

Given these are legacy. I think we can remove those tests to move forward

[tqchen]

would be great to check the remaining errors and get this in

[tqchen]

superseded by #17920