Improve robustness of dumping time.Time timezone.

The String method of time.Local may not always return "Local", e.g., if
TZ variable is set to another timezone, or if local timezone happens to
be UTC anyway.

dump.go

@@ -146,7 +146,16 @@ func (d *dumpState) dump(v reflect.Value) {
 		t := v.Interface().(time.Time)
 		switch t.IsZero() {
 		case false:
-			fmt.Fprintf(d.w, "time.Date(%d, %d, %d, %d, %d, %d, %d, time.%s)", t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), t.Location().String())
+			var location string
+			switch t.Location() {
+			case time.UTC:
+				location = "time.UTC"
+			case time.Local:
+				location = "time.Local"
+			default:
+				location = fmt.Sprintf("must(time.LoadLocation(%q))", t.Location().String())
+			}
+			fmt.Fprintf(d.w, "time.Date(%d, %d, %d, %d, %d, %d, %d, %s)", t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), location)
 		case true:
 			d.w.Write([]byte("time.Time{}"))
 		}