`merge` raises internal ugly error on CH if types are not compatible

[shcheklein]

DB::Exception: There is no supertype for types String, Int64 because some of them are String/FixedString/Enum and some of them are not: JOIN  INNER JOIN ... ON PKgFxBXUIkWjxKAV.file_id = avtEcmyNKoXggsXh.file_id cannot infer common type in ON section for keys. Left key __table1.file_id type String. Right key __table3.file_id type Int64. Stack trace:

We need to check schema and don't allow this