Move SuspendFunction{N} interfaces to kotlin.coroutines package

#KT-25824: Fixed

core/builtins/native/kotlin/Coroutines.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.coroutines
+
+/**
+ * This is neccesary to force generation of coroutines.kotlin_builtins file, thus providing builtin package fragment for kotlin.coroutines
+ * package. This way we can use kotlin.coroutines.SuspendFunction{N} interfaces in code.
+ */
+private fun hackToForceKotlinBuiltinsForKotlinCoroutinesPackage() {}