test: add test for export/import of recover & defer

Add a simple test with an exported generic function that does
recover/defer, to test that recover/defer are exported/imported
properly (and a generic function with recover/defer works fine).

Change-Id: Idc3af101cbb78fc96bf945f1f5eab2740dd8994b
Reviewed-on: https://go-review.googlesource.com/c/go/+/353883
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>

test/typeparam/recoverimp.dir/a.go

@@ -0,0 +1,16 @@
+// Copyright 2021 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.
+
+package a
+
+import "fmt"
+
+func F[T any](a T) {
+	defer func() {
+		if x := recover(); x != nil {
+			fmt.Printf("panic: %v\n", x)
+		}
+	}()
+	panic(a)
+}

test/typeparam/recoverimp.dir/main.go

@@ -0,0 +1,12 @@
+// Copyright 2021 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.
+
+package main
+
+import "a"
+
+func main() {
+	a.F(5.3)
+	a.F("hello")
+}

test/typeparam/recoverimp.go

@@ -0,0 +1,7 @@
+// rundir -G=3
+
+// Copyright 2021 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.
+
+package ignored

test/typeparam/recoverimp.out

@@ -0,0 +1,2 @@
+panic: 5.3
+panic: hello