JVM IR: fix incorrect IR types in inner and enum class lowerings

In InnerClassesLowering, the type of the "outer$0" expression should be
the outer class, not the inner class. In EnumClassLowering, the type of
the enum entry is the type of its class or the type of the enum class,
but not the type of initialierExpression which is always Unit

compiler/testData/codegen/box/classes/kt2566_2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 open class A {
     open val foo: String = "OK"
 }