Deserialize experimental coroutines as suspend functions/types

but deprecate them for now.
Promote stub version.
 #KT-25623: Fixed

compiler/testData/compileKotlinAgainstCustomBinaries/experimentalCoroutineCallFromRelease/library/experimental.kt

@@ -0,0 +1,27 @@
+suspend fun dummy() {}
+
+class C {
+    suspend fun dummy() = "OK"
+}
+
+class WithNested {
+    class Nested {
+        suspend fun dummy() = "OK"
+    }
+}
+
+class WithInner {
+    inner class Inner {
+        suspend fun dummy() = "OK"
+    }
+}
+
+val c: suspend () -> Unit = {}
+
+class WithTypeParameter<T: suspend() -> Unit> {}
+
+fun returnsSuspend() : suspend() -> Unit = {}
+
+fun builder(c: suspend () -> Unit) {}
+
+fun <T: suspend () -> Unit> withTypeParameter() = {}