[IntToBV] Add check for unsupported operators (#8949)

[IntToBV] Add check for unsupported operators (#8949)

Fixes #8935. This adds a check for unsupported operators in the IntToBV
preprocessing pass and improves error messages. Previously, operators
such as str.to_int, which return an integer but do not take an integer
as an argument were not detected as unsupported.