Disable run-test 920-objects on jit-on-first-use configuration.

Temporarily disable this test to keep the build green, while we
investigate the crashes.

Test: Rely on the Android Build continuous testing
Bug: 117638896
Change-Id: Iec5cab885a99d504fde77aa5ee4ab1af65ff5fa5
diff --git a/test/knownfailures.json b/test/knownfailures.json
index 4e3ec24..8aa5979 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -1106,5 +1106,11 @@
         "variant": "target & gcstress & debug",
         "bug": "b/117597114",
         "description": ["Looks timing dependent"]
+    },
+    {
+        "tests": ["920-objects"],
+        "variant": "jit-on-first-use",
+        "bug": "b/117638896",
+        "description": ["SIGSEGVs on jit-on-first-use configuration."]
     }
 ]