KT-23394: Add a test with a property

idea/testData/quickfix/typeMismatch/variableInitializedWithNullProperty.kt

@@ -0,0 +1,10 @@
+// "Change type of 'Foo.x' to 'String?'" "true"
+class Foo {
+    var x = null
+
+    fun foo(condition: Boolean) {
+        if (condition) {
+            x = "abc"<caret>
+        }
+    }
+}

idea/testData/quickfix/typeMismatch/variableInitializedWithNullProperty.kt.after

@@ -0,0 +1,10 @@
+// "Change type of 'Foo.x' to 'String?'" "true"
+class Foo {
+    var x: String? = null
+
+    fun foo(condition: Boolean) {
+        if (condition) {
+            x = "abc"<caret>
+        }
+    }
+}