Render unwrapped suspend function in backend

Hierarchy of specially wrapped suspend function may have inconsistent
 overridden descriptors: some of them may be wrapped, some unwrapped.
 To mitigate this problem, currently it's proposed to render only
 unwrapped functions, which are always have stable overridden descriptors

 #KT-23809 Fixed

compiler/testData/codegen/dumpDeclarations/intermediateAbstractSuspendFunction.json

@@ -0,0 +1,44 @@
+[
+	{
+		"declaration": "abstract class C<V> : B<V> defined in root package",
+		"visibility": "public",
+		"class": "C",
+		"members": [
+			{"visibility": "public",	"declaration": "open suspend fun foo(): V", "name": "foo", "desc": "(Lkotlin/coroutines/experimental/Continuation;)Ljava/lang/Object;"},
+			{"visibility": "public",	"declaration": "open suspend fun foo(): V", "name": "foo$suspendImpl", "desc": "(LC;Lkotlin/coroutines/experimental/Continuation;)Ljava/lang/Object;"},
+			{"visibility": "public",	"declaration": "constructor C<V>()", "name": "<init>", "desc": "()V"}
+		]
+	},
+	{
+		"declaration": "interface B<K> : A<K> defined in root package",
+		"visibility": "public",
+		"class": "B$DefaultImpls",
+		"members": [
+
+		]
+	},
+	{
+		"declaration": "interface B<K> : A<K> defined in root package",
+		"visibility": "public",
+		"class": "B",
+		"members": [
+
+		]
+	},
+	{
+		"declaration": "interface A<T> defined in root package",
+		"visibility": "public",
+		"class": "A$DefaultImpls",
+		"members": [
+
+		]
+	},
+	{
+		"declaration": "interface A<T> defined in root package",
+		"visibility": "public",
+		"class": "A",
+		"members": [
+			{"visibility": "public",	"declaration": "abstract suspend fun foo(): T", "name": "foo", "desc": "(Lkotlin/coroutines/experimental/Continuation;)Ljava/lang/Object;"}
+		]
+	}
+]