FIR: Support inferring PRIVATE_TO_THIS visibility see KT-49875

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

@@ -0,0 +1,14 @@
+// FIR_DUMP
+
+class A<in T>(t: T) {
+    private val t: T = t  // PRIVATE_TO_THIS
+
+    fun test() {
+        val x: T = t      // Ok
+        val y: T = this.t // Ok
+    }
+
+    fun foo(a: A<String>) {
+        val x: String = a.<!INVISIBLE_MEMBER!>t<!> // Invisible!
+    }
+}