tests: sort import lines in dumbhttp.py This series is an attempt to enable import-checker.py for tests/**.py, but it turned out not easy. Since many tests have been ported to absolute_import without the coverage, import-checker.py reports a lot of errors right now. Should we enable import-checker.py without fixing all of them so that we won't get more errors?

--- a/tests/dumbhttp.py	Mon Apr 04 01:59:57 2016 +0100
+++ b/tests/dumbhttp.py	Sun Apr 03 19:40:05 2016 +0900
@@ -6,10 +6,10 @@
 Small and dumb HTTP server for use in tests.
 """
 
+import BaseHTTPServer
+import SimpleHTTPServer
 import optparse
-import BaseHTTPServer
 import signal
-import SimpleHTTPServer
 import sys
 
 from mercurial import (