sync: really test DeepCopyMap

since there current version suffers from a copy'n'paste error.

Change-Id: I1ef97a4413198dde10c5c926a2a9806724cd6d44
Reviewed-on: https://go-review.googlesource.com/42095Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/sync/map_test.go

@@ -103,7 +103,7 @@ func TestMapMatchesRWMutex(t *testing.T) {
 }
 
 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)
 	}
 }