FIR: Refine visibility check for private methods defined in a class

- use-site should be contained within the class that owns callee symbol
- class-representative of dispatch receiver value
should be exactly the same as a container class of a callee (not its subtype)

compiler/testData/diagnostics/tests/visibility/invisiblePrivateThroughSubClass.fir.kt

@@ -0,0 +1,11 @@
+// SKIP_TXT
+
+abstract class A {
+    fun foo(b: B) {
+        b.<!INVISIBLE_REFERENCE!>prv<!>()
+    }
+
+    private fun prv() {}
+}
+
+abstract class B : A()

compiler/testData/diagnostics/tests/visibility/invisiblePrivateThroughSubClass.kt

@@ -0,0 +1,11 @@
+// SKIP_TXT
+
+abstract class A {
+    fun foo(b: B) {
+        b.<!INVISIBLE_MEMBER!>prv<!>()
+    }
+
+    private fun prv() {}
+}
+
+abstract class B : A()