This commit introduces MppChecker kind, which represents the new property
of checkers
- `MppCheckerKind.Common` means that this checker should run from the same
session to which corresponding declaration belongs
- `MppCheckerKind.Platform` means that in case of MPP compilation this
checker should run with session of leaf platform module for sources
of all modules
An example of a platform checker is a checker that checks class scopes
and reports ABSTRACT_NOT_IMPLEMENTED and similar diagnostics. If some
regular class in the common module contains expect supertypes, the
checker should consider the actualization of those supertypes to get
a complete type scope
^KT-58881
Marco Pennekamp