Add test case to check delegation of suspend method

compiler/testData/codegen/box/coroutines/delegatedSuspendMember.kt

@@ -0,0 +1,31 @@
+// WITH_COROUTINES
+// COMMON_COROUTINES_TEST
+
+import helpers.*
+import COROUTINES_PACKAGE.*
+import COROUTINES_PACKAGE.intrinsics.*
+
+var result = "fail"
+
+interface SuspendInterface {
+    suspend fun foo(v: String)
+}
+
+class Delegate : SuspendInterface {
+    override suspend fun foo(v: String) {
+        result = v
+    }
+}
+
+class Decorator(parent: SuspendInterface) : SuspendInterface by parent
+
+fun execute(c: suspend () -> Unit) = c.startCoroutine(EmptyContinuation)
+
+fun box(): String {
+
+    execute {
+        Decorator(Delegate()).foo("OK")
+    }
+
+    return result
+}