unwrapCompanionClass fails to unwrap private companions when on kotlin 1.4+

[ilya-yamschikov]

I have a class with a companion object that extends KLogging(). I expect that the logger name would contain just the enclosing class name without the companion object class name. Even when a companion object is private.
This works fine when compiling it with kotlin 1.3 and below. This doesn't work with 1.4+.

Consider an example:

class PublicCompanion {
    public companion object : KLogging()
    val loggerName = logger.name
}

class PrivateCompanion {
    private companion object : KLogging()
    val loggerName = logger.name
}

fun main() {
    println(PublicCompanion().loggerName)
    println(PrivateCompanion().loggerName)
}

When compiling with kotlin 1.3 it outputs:

PublicCompanion
PrivateCompanion

While with 1.4 it changes to:

PublicCompanion
PrivateCompanion$Companion

There was a change in what visibility modifiers are put into bytecode by the kotlin compiler:
https://kotlinlang.org/docs/compatibility-guide-14.html#the-instance-field-of-a-companion-object-more-visible-than-the-companion-object-class-itself
As a reslut a reflection method that is used by unwrapCompanionClass started failing on private companions.
So that it doesn't unwrap companion class name when it's private any more.