Add a test case for rust-lang#102383

Author: eholk

tests/ui/async-await/await-sequence.rs

@@ -0,0 +1,21 @@
+// edition:2021
+// compile-flags: -Z drop-tracking
+// build-pass
+
+use std::collections::HashMap;
+
+fn main() {
+    let _ = real_main();
+}
+
+async fn nop() {}
+
+async fn real_main() {
+    nop().await;
+    nop().await;
+    nop().await;
+    nop().await;
+
+    let mut map: HashMap<(), ()> = HashMap::new();
+    map.insert((), nop().await);
+}