Add roundtrip test for subkey expires

Former-commit-id: 56fc6b7deb59cfb3219d65c01c96969d3983e84a

tests/unit/expire.tcl

@@ -252,4 +252,13 @@ start_server {tags {"expire"}} {
         r expiremember testkey foo 10000
         assert [expr [r ttl testkey foo] > 0]
     }
+
+    test {Roundtrip for subkey expires works} {
+        r flushall
+        r sadd testkey foo bar baz
+        r expiremember testkey foo 10000
+        r save
+        r debug reload
+        assert [expr [r ttl testkey foo] > 0]
+    }
 }