handle semicolons in "introduce backing property"

#KT-9417 Fixed

idea/testData/intentions/introduceBackingProperty/semicolon.kt

@@ -0,0 +1,3 @@
+class City(val name: String) {
+    var ti<caret>meZone : Int = -3;
+}

idea/testData/intentions/introduceBackingProperty/semicolon.kt.after

@@ -0,0 +1,8 @@
+class City(val name: String) {
+    private var _timeZone: Int = -3
+    var timeZone : Int
+        get() = _timeZone
+        set(value) {
+            _timeZone = value
+        };
+}