KT-2228 Open and final trait members are loaded as abstract from binary Kotlin classes.

Added storing modality for trait members in @JetMethod annotations.

 #KT-2228 Fixed

compiler/testData/readKotlinBinaryClass/classFun/TraitOpenFun.kt

@@ -0,0 +1,7 @@
+// KT-2228
+
+package test
+
+trait A {
+    fun f(): String = "test"
+}