Remove check in visibilities that allowed access to privates of outer packages

It doesn't work for a while now in imports and is planned to be dropped with upcoming changes to private

compiler/testData/diagnostics/tests/PrivateFromOuterPackage.kt

@@ -0,0 +1,25 @@
+// FILE: a.kt
+package outer
+
+private fun a() {}
+private class B
+
+// FILE: b.kt
+package outer.p1
+
+import outer.<!INVISIBLE_REFERENCE!>a<!>
+
+fun use() {
+    <!INVISIBLE_MEMBER!>a<!>()
+    outer.<!INVISIBLE_MEMBER!>B<!>()
+}
+
+// FILE: c.kt
+package outer.p1.p2
+
+import outer.<!INVISIBLE_REFERENCE!>a<!>
+
+fun use() {
+    <!INVISIBLE_MEMBER!>a<!>()
+    outer.<!INVISIBLE_MEMBER!>B<!>()
+}