Implement members: don't add 'actual' modifier for fake overrides

#KT-25044 Fixed

idea/testData/multiModuleQuickFix/implementMembersInActualClassNoExpectMember/common/common.kt

@@ -0,0 +1,5 @@
+expect interface ExpInterface {
+    fun first()
+}
+
+expect class ExpImpl : ExpInterface { }

idea/testData/multiModuleQuickFix/implementMembersInActualClassNoExpectMember/common/common.kt.after

@@ -0,0 +1,5 @@
+expect interface ExpInterface {
+    fun first()
+}
+
+expect class ExpImpl : ExpInterface { }