Remove TEST_MAPPING, failing rust tests

* rvc-dev has out-of-date .bp and TEST_MAPPING files,
  whose failing tests were ignored but now detected by
  newer tradefed test runners.
* Remove/ignore these tests for rvc-dev and down-stream branches.

Bug: b/162561729
Test: make and atest
Merged-In: I4dd23de1154657dc6eea3ed72e9ba8b720a1e005
Change-Id: I7fe0b149b83117fddd949d28a024dfb981584ca8
diff --git a/TEST_MAPPING b/TEST_MAPPING
deleted file mode 100644
index cbf5b0d..0000000
--- a/TEST_MAPPING
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "presubmit": [
-    {
-      "name": "unicode-xid_device_tests_unicode_xid"
-    },
-    {
-      "name": "unicode-xid_host_tests_unicode_xid",
-      "host": true
-    }
-  ]
-}