There are only simple checks for `external` and `const` for now. The
rest of the checks (see ModifiersChecker in FE1.0) will be added later.

If sources contain module-info.java javac tries to validate modules existence/visibility during AP phase and fails, because we don't specify modules-path/patch-module. All these checks will be done in kotlin compiler and in javac for java classes. And it is not necessary to do it in AP too.
So we go for easiest path possible - disable jpms for AP. 

#KT-32202 Fixed

The `clone` function is not available in the builtin classes created
from fir.

If a type paramter is not reified or nullable, different errors will
be reported by FirGetClassCallChecker.

When determining whether type parameter wrapped in qualified access is a
standalone expression or not, we examine whether the checker context has
other qualified accesses in stack. Class literals (::class) is desugared
to FirGetClassCall, and thus not stacked as qualified access. Since
class literals are a special type of callable reference (a subtype of
qualified access), we should keep track of FirGetClassCall in a similar
way.