Ignore flaky ApexSystemServicesTestCases.

It seems depending on logcat output for signaling introduces a
persistent flakiness to the tests. Mark them @Ignore until a better
solution is available, which disables the tests on presubmit.

The test is still part of mts-core which shouldn't be ignoring these
test cases though.

Bug: 218368479
Test: presubmit
Change-Id: I154e7fecab044d1f6406b98be8e3873a6ff03c5e
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 81e4fcb..b43eb7e 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -26,6 +26,9 @@
       "options": [
         {
           "exclude-annotation": "androidx.test.filters.FlakyTest"
+        },
+        {
+          "exclude-annotation": "org.junit.Ignore"
         }
       ]
     },