test: add test that caused a gofrontend crash

For #55242

Change-Id: I092b1881623ea997b178d038c0afd10cd5bca937
Reviewed-on: https://go-review.googlesource.com/c/go/+/479898
Reviewed-by: Than McIntosh <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Matthew Dempsky <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: ianlancetaylor

test/fixedbugs/issue55242.go

@@ -0,0 +1,18 @@
+// compile
+
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 55242: gofrontend crash calling function that returns
+// trailing empty struct.
+
+package p
+
+func F1() (int, struct{}) {
+	return 0, struct{}{}
+}
+
+func F2() {
+	F1()
+}