Extract Function: Add support of initializer expressions

idea/testData/refactoring/extractFunction/initializers/classes/classParameters.kt.after

@@ -0,0 +1,7 @@
+// PARAM_TYPES: kotlin.Int
+val n = 1
+class A(val a: Int, val b: Int = i(a))
+
+fun i(a: Int): Int {
+    return a + n
+}