Add pinned async stream test

Author: raviqqe

futures/tests/async_await/pinned.rs

@@ -33,7 +33,16 @@ fn spawnable() -> Result<(), Never> {
 }
 
 #[async_stream(item = u64)]
-fn _stream1() -> Result<(), i32> {
+fn _stream() -> Result<(), i32> {
+    fn integer() -> u64 { 1 }
+    let x = &integer();
+    stream_yield!(0);
+    stream_yield!(*x);
+    Ok(())
+}
+
+#[async_stream(pinned, item = u64)]
+fn _stream_boxed() -> Result<(), i32> {
     fn integer() -> u64 { 1 }
     let x = &integer();
     stream_yield!(0);