Generate synthetic methods for annotated properties in TImpl classes

Traits themselves can't have these methods, since it'd be a weird public method
in an interface

 #KT-4072 Fixed

compiler/testData/codegen/properties/syntheticMethod/inTrait.kt

@@ -0,0 +1,7 @@
+import java.lang.annotation.*
+
+Retention(RetentionPolicy.RUNTIME) annotation class SomeAnnotation(val value: String)
+
+trait T {
+    [SomeAnnotation("OK")] val property: Int
+}