Revert "Adding screenshot tests to postsubmit."

This reverts commit ade491b4667850ac39da55bde9b74f45c22324d0.

Reason for revert: Missing test_suite b/315860052

Change-Id: Ie64aa53f6d327f4710db491415263c586e52a8c4
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 8278978..9722a85 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -37,10 +37,6 @@
     },
     {
       "name": "SettingsPerfTests"
-    },
-    {
-      "name": "SettingsScreenshotRNGTests",
-      "host": true
     }
   ]
 }