Tests need update #2901
Description
After [cfe] Add SourceLibraryBuilder.prefixNameSpace.
The tests
co19/Language/Libraries_and_Scripts/Imports/namespace_changes_t23 MissingCompileTimeError (expected Pass)
co19/Language/Libraries_and_Scripts/Imports/namespace_changes_t26 MissingCompileTimeError (expected Pass)
needs to be updated to match the new messages.