Extract property: do not suggest duplicate property name

#KT-36504 Fixed

idea/testData/refactoring/introduceProperty/conflictWithParentClass.kt

@@ -0,0 +1,8 @@
+// EXTRACTION_TARGET: property with initializer
+open class Base(protected val i: Int)
+
+class Impl(z: Int) : Base(z) {
+    fun foo(): Int {
+        return <selection>2 + 3 + i</selection>
+    }
+}

idea/testData/refactoring/introduceProperty/conflictWithParentClass.kt.after

@@ -0,0 +1,10 @@
+// EXTRACTION_TARGET: property with initializer
+open class Base(protected val i: Int)
+
+class Impl(z: Int) : Base(z) {
+    private val i1 = 2 + 3 + i
+
+    fun foo(): Int {
+        return i1
+    }
+}

idea/testData/refactoring/introduceProperty/kt24615.kt.after

@@ -3,10 +3,10 @@
 open class Base(protected val i: Int)
 
 class Impl(i: Int) : Base(i) {
-    private val i: Int
+    private val i1: Int
         get() = 2 + 3 + i
 
     fun foo(): Int {
-        return i
+        return i1
     }
 }