syncmap: backport CL 42095

See https://go-review.googlesource.com/c/42095/.

Change-Id: I9f15a785bb4bd28ab02f17de65c63ad4b6e083c9
Reviewed-on: https://go-review.googlesource.com/42594
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/syncmap/map_test.go b/syncmap/map_test.go
index a60bbed..c883f17 100644
--- a/syncmap/map_test.go
+++ b/syncmap/map_test.go
@@ -105,7 +105,7 @@
 }
 
 func TestMapMatchesDeepCopy(t *testing.T) {
-	if err := quick.CheckEqual(applyMap, applyRWMutexMap, nil); err != nil {
+	if err := quick.CheckEqual(applyMap, applyDeepCopyMap, nil); err != nil {
 		t.Error(err)
 	}
 }