[FIR] Prefer the non-smartcasted receiver in resolution if it's visible

Previously, we would ignore the candidate with the non-smartcasted
receiver if they have the same symbol.
Now we prefer them when they're visible or when the smart cast changes
the nullability.

compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.fir.kt

@@ -27,4 +27,21 @@ class Derived : Base() {
             x.y = x.y + 1
         }
     }
+
+    protected fun baz2(x: Base?) {
+        x.<!INVISIBLE_REFERENCE!>foo<!>()
+        x.<!INVISIBLE_REFERENCE!>bar<!>()
+
+        x.<!INVISIBLE_REFERENCE!>x<!> = x.<!INVISIBLE_REFERENCE!>x<!> + 1
+        x.<!INVISIBLE_SETTER!>y<!> = x<!UNSAFE_CALL!>.<!>y + 1
+
+        if (x is Derived) {
+            x.foo()
+            x.bar()
+            x.baz(x)
+
+            x.x = x.x + 1
+            x.y = x.y + 1
+        }
+    }
 }