Add rustdoc tests from rust-lang#72088

Author: ecstatic-morse

src/test/rustdoc/macro-in-async-block.rs

@@ -0,0 +1,9 @@
+// Regression issue for rustdoc ICE encountered in PR #72088.
+// edition:2018
+#![feature(decl_macro)]
+
+fn main() {
+    async {
+        macro m() {}
+    };
+}

src/test/rustdoc/macro-in-closure.rs

@@ -6,4 +6,11 @@ fn main() {
     || {
         macro m() {}
     };
+
+    let _ = || {
+        macro n() {}
+    };
+
+    let cond = true;
+    let _ = || if cond { macro n() {} } else { panic!() };
 }