Refactor KClassValue to store ClassLiteralValue internally

Only invariant array projections and non-null element types will be
supported soon (see KT-26568), so it makes no sense to store the
complete type in KClassValue. What we need is only the ClassId of the
class, and the number of times it's wrapped into kotlin/Array, which is
exactly what ClassLiteralValue represents.

This change helps in decoupling annotation values from
descriptors/types. The only constant value that depends on descriptors
is now AnnotationValue.

 #KT-26582 Fixed

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/ConstantValueGenerator.kt

@@ -85,7 +85,7 @@ class ConstantValueGenerator(
             is AnnotationValue -> generateAnnotationConstructorCall(constantValue.value)
 
             is KClassValue -> {
-                val classifierKtType = constantValue.value
+                val classifierKtType = constantValue.getArgumentType(moduleDescriptor)
                 val classifierDescriptor = classifierKtType.constructor.declarationDescriptor
                         ?: throw AssertionError("Unexpected KClassValue: $classifierKtType")