There's a separate test data directory `testsWithJvmBackend` with a
runner that properly invokes the JVM backend and reports diagnostics
from it. All tests where JVM diagnostic presence/absence is important
were copied/moved there in this and previous commits.
The problem with the code removed in this commit is that it invoked some
parts of the _old JVM backend_ and old light classes, which is very far
from what users see in the production compiler at this point. This led
to real issues where we implemented incorrect behavior in K2 based on
the misleading diagnostic report from the K1 test.
The diagnostic in `triangleWithFlexibleTypeAndSubstitution4.kt` was
removed, but there's a copy of this test in `codegen/box/javaInterop`
which fails for K2 (KT-66529).
The diagnostic in `intersectionWithMappedSignature.kt` was removed and
that is OK because at this point CONFLICTING_JVM_DECLARATIONS there
seems like a bug in the old JVM backend.
A class can inherit two declarations that are compatible from the
overridability standpoint and are therefore combined to a non-trivial
intersection.
At the same time, the class can declare a member declaration that
only overrides one of the intersection's members.
In this case, we break up the intersection and only add the overridden
parts to the declared member's direct overridden list.
If the class doesn't override the intersection, it exists as
intersection override, like before.
#KT-65487 Fixed