If the type of a node cannot be determined due to a previous type error,
a "no type for node" ICE occurs. This commit makes it return ty_err
instead in such a case.
Fixes#20401.
Fixes#20506.
Fixes#20614.
Fixes#20752.
Fixes#20829.
Fixes#20846.
Fixes#20885.
Fixes#20886.