Updating pre/post submit tests

Adding SurfaceFlinger_test to presubmit, and sffakehwc_test
to postsubmit.

Bug: 160796914
Test: atest -s 127.0.0.1:37975 --test-mapping TEST_MAPPING:presubmit
Test: atest -s 127.0.0.1:38029 --test-mapping TEST_MAPPING:postsubmit
Change-Id: I0c36ec37f7876e8714a7efe2cf8787a36543562b
diff --git a/services/surfaceflinger/TEST_MAPPING b/services/surfaceflinger/TEST_MAPPING
index cab33ae..e530ff9 100644
--- a/services/surfaceflinger/TEST_MAPPING
+++ b/services/surfaceflinger/TEST_MAPPING
@@ -5,6 +5,14 @@
     },
     {
       "name": "libcompositionengine_test"
+    },
+    {
+      "name": "SurfaceFlinger_test"
+    }
+  ],
+  "postsubmit": [
+    {
+      "name": "sffakehwc_test"
     }
   ]
 }