Extract Function: Check for INVISIBLE_* errors during validation phase

#KT-4995 Fixed

idea/testData/refactoring/extractFunction/basic/privateMemberInClassObject.kt

@@ -0,0 +1,9 @@
+// SIBLING:
+public class A {
+    class object {
+        private val t: Int = 1
+    }
+    fun f() {
+        <selection>t</selection>
+    }
+}

idea/testData/refactoring/extractFunction/basic/privateMemberInClassObject.kt.conflicts

@@ -0,0 +1 @@
+Property A.t will become invisible after extraction

idea/testData/refactoring/extractFunction/basic/privateNestedClass.kt

@@ -0,0 +1,7 @@
+// SIBLING:
+public class A {
+    private class B
+    fun f() {
+        <selection>val b: A.B</selection>
+    }
+}

idea/testData/refactoring/extractFunction/basic/privateNestedClass.kt.conflicts

@@ -0,0 +1 @@
+Class A.B will become invisible after extraction

idea/testData/refactoring/extractFunction/basic/privateSetter.kt

@@ -0,0 +1,9 @@
+// SIBLING:
+class A {
+    var t = 1
+        private set
+
+    fun test() {
+        <selection>t = 5</selection>
+    }
+}

idea/testData/refactoring/extractFunction/basic/privateSetter.kt.conflicts

@@ -0,0 +1 @@
+Setter of property A.t will become invisible after extraction