This will be needed in subsequent commits because context must be
accessible from `:fir:checkers` module, but it is in `:fir:resolve`
Intermediate interface `FirExpectActualMatchingContext` is needed
because `FirExpectActualResolver` relies on some FIR-specific methods,
and providing common `ExpectActualMatchingContext` interface is not
enough.
Also in `FirExpectActualMatcherTransformer` context extracted to field
to not create context for each processed element. "session" made
final to calm down warning "accessing non-final property in
constructor".
^KT-58551
Roman Efremov
b1bdb619d8