Drop GkiInstallTest from TEST_MAPPING.

The test no longer matters and we do not care about whether
it regresses or not.

Test: TH
Bug: 259427298
Change-Id: I28d86b453633afd0c15e2cb1ce021c05fb0c49f9
(cherry picked from commit ece1d1dfd23111d99878349b216370852f6e98e4)
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 592bd85..ce2bc64 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -2,9 +2,6 @@
   "presubmit": [
     {
       "name": "libkver_test"
-    },
-    {
-      "name": "GkiInstallTest"
     }
   ]
 }