Invert the logic of IR/FIR2IR-based generators: change the CLI argument
to -Xuse-fir-fake-override-builder, test directive to
USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR, etc.
The changes in test data caused by using IR fake override builder by
default are in the subsequent commit.
#KT-61514
Unfortunately, it's not enough to know direct overriddens
to correctly build fake overrides. This mean, that we need to know
whole overridden tree during the process of building.
It happens automatically for normal classes, but not for lazy classes,
as their overriddens are built separatly.
This commit enforces correct overrddens for lazy classes in hierarhies
at the point, where they should be normally computed.
^KT-65236
Alexander Udalov