Push Down: Initial Support

idea/testData/refactoring/pushDown/pushClassMembersAndMakeAbstract.kt

@@ -0,0 +1,34 @@
+abstract class <caret>A {
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    val x = 1
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    val y: Int get() = 2
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    val z: Int by lazy { 3 }
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    abstract val t: Int
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    fun foo(n: Int): Boolean = n > 0
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    abstract fun bar(s: String)
+
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    inner class X {
+
+    }
+
+    // INFO: {"checked": "true", "toAbstract": "true"}
+    class Y {
+
+    }
+}
+
+abstract class B : A() {
+
+}
+
+class C : A() {
+    override val t = 1
+
+    override fun bar(s: String) = s.length()
+}