Sort tests.json alphabetically

src/python/grpcio_tests/tests_aio/tests.json

@@ -17,7 +17,6 @@
   "unit.channel_argument_test.TestChannelArgument",
   "unit.channel_ready_test.TestChannelReady",
   "unit.channel_test.TestChannel",
-  "unit.context_peer.TestContextPeer",
   "unit.client_stream_stream_interceptor_test.TestStreamStreamClientInterceptor",
   "unit.client_stream_unary_interceptor_test.TestStreamUnaryClientInterceptor",
   "unit.client_unary_stream_interceptor_test.TestUnaryStreamClientInterceptor",
@@ -27,6 +26,7 @@
   "unit.compatibility_test.TestCompatibility",
   "unit.compression_test.TestCompression",
   "unit.connectivity_test.TestConnectivityState",
+  "unit.context_peer.TestContextPeer",
   "unit.done_callback_test.TestDoneCallback",
   "unit.init_test.TestChannel",
   "unit.metadata_test.TestMetadata",