THRIFT-4621 Add THeader for Python

Client: py
diff --git a/test/tests.json b/test/tests.json
index 72790ac..85a0c07 100644
--- a/test/tests.json
+++ b/test/tests.json
@@ -273,7 +273,8 @@
       "binary",
       "json",
       "binary:accel",
-      "compact:accelc"
+      "compact:accelc",
+      "header"
     ],
     "workdir": "py"
   },
@@ -319,7 +320,8 @@
       "binary",
       "json",
       "binary:accel",
-      "compact:accelc"
+      "compact:accelc",
+      "header"
     ],
     "workdir": "py"
   },