Introduce Variable: Do not replace assignment left-hand sides

#KT-14240 Fixed

idea/testData/refactoring/introduceVariable/skipUsageInAssignmentLHS.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class Foo(var bar: Int)
+
+fun test() {
+    val foo = Foo(1)
+    println(<selection>foo.bar</selection>)
+    foo.bar = foo.bar + 1
+}