[mlir] Allow to override type/attr aliases from various hooks

[mlir] Allow to override type/attr aliases from various hooks

Use new return type for `OpAsmDialectInterface::getAlias`:

* `AliasResult::NoAlias` if an alias was not provided.
* `AliasResult::OverridableAlias` if an alias was provided, but it might be overriden by other hook.
* `AliasResult::FinalAlias` if an alias was provided and it should be used (no other hooks will be checked).

In that case `AsmPrinter` will use either the first alias with `FinalAlias` result or
the last alias with `OverridableAlias` result (it depends on dialect array order).

Used `OverridableAlias` result for `BuiltinOpAsmDialectInterface`.

Use case: provide more informative alias for built-in attributes like `AffineMapAttr`
instead of generic "map<N>".

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D107437