unittest: Print no. of skipped tests in a way compatible with CPython.

Perhaps, modern CPython (3.8).

Signed-off-by: Paul Sokolovsky <pfalcon@users.sourceforge.net>

python-stdlib/unittest/unittest.py

@@ -237,7 +237,7 @@ class TestRunner:
         else:
             msg = "OK"
             if res.skippedNum > 0:
-                msg += " (%d skipped)" % res.skippedNum
+                msg += " (skipped=%d)" % res.skippedNum
             print(msg)
 
         return res