test: Rename final check in setexpr_test_backref()

The bug in setexpr is fixed now, so this test can be enabled.

Reported-by: Coverity (CID: 316346)

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/cmd/setexpr.c b/test/cmd/setexpr.c
index c537e89..08b6e6e 100644
--- a/test/cmd/setexpr.c
+++ b/test/cmd/setexpr.c
@@ -270,8 +270,6 @@
 	ut_asserteq_str("us this is surely! a test is it? yes us this is indeed! a test",
 			buf);
 
-	/* The following checks fail at present due to a bug in setexpr */
-	return 0;
 	for (i = BUF_SIZE; i < 0x1000; i++) {
 		ut_assertf(buf[i] == (char)i,
 			   "buf byte at %x should be %02x, got %02x)\n",