K2: introduce platform-specific visibility checks for overrides + tests

Related to KT-53197

compiler/testData/ir/irText/firProblems/internalPotentialOverride.kt

@@ -0,0 +1,14 @@
+// TARGET_BACKEND: JVM_IR
+// MODULE: m1
+// FILE: A.kt
+
+open class A {
+    internal open fun foo() : Int = 1
+}
+
+// MODULE: m2(m1)
+// FILE: B.kt
+
+class B : A() {
+    fun foo() : String = "OK"
+}