test: add test case for issue 53702

The issue is expected to be fixed when Unified IR is enabled by default,
so adding a test to make sure thing works correctly.

Updates #53702

Change-Id: Id9d7d7ca4506103df0d10785ed5ee170d69988ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/423434
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>

test/fixedbugs/issue53702.go

@@ -0,0 +1,39 @@
+// run
+
+// Copyright 2022 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
+
+type Elem struct{}
+
+func (*Elem) Wait(callback func()) {}
+
+type Base struct {
+	elem [8]*Elem
+}
+
+var g_val = 1
+
+func (s *Base) Do() *int {
+	resp := &g_val
+	for _, e := range s.elem {
+		e.Wait(func() {
+			*resp = 0
+		})
+	}
+	return resp
+}
+
+type Sub struct {
+	*Base
+}
+
+func main() {
+	a := Sub{new(Base)}
+	resp := a.Do()
+	if resp != nil && *resp != 1 {
+		panic("FAIL")
+	}
+}

test/run.go

@@ -1976,6 +1976,7 @@ var types2Failures32Bit = setOf(
 )
 
 var go118Failures = setOf(
+	"fixedbugs/issue53702.go",  // 1.18 compiler failed with "Value live at entry" error
 	"fixedbugs/issue54343.go",  // 1.18 compiler assigns receiver parameter to global variable
 	"typeparam/nested.go",      // 1.18 compiler doesn't support function-local types with generics
 	"typeparam/issue51521.go",  // 1.18 compiler produces bad panic message and link error