Clean up rust_test_host TEST_MAPPING after default update

After b/177689340, rust_test_host doesn't need TEST_MAPPING config anymore to run in
presubmit.

Change-Id: I2e273a25e2cd119d08770473623afe54b8fbe354
Test: presubmit
Bug: 178646865
diff --git a/cras/client/cras-sys/TEST_MAPPING b/cras/client/cras-sys/TEST_MAPPING
deleted file mode 100644
index 29bd3e1..0000000
--- a/cras/client/cras-sys/TEST_MAPPING
+++ /dev/null
@@ -1,13 +0,0 @@
-// Generated by cargo2android.py for tests in Android.bp
-{
-  "presubmit": [
-    {
-      "name": "cras-sys_host_test_src_lib",
-      "host": true
-// Presubmit tries to run x86, but we only support 64-bit builds.
-//    },
-//    {
-//      "name": "cras-sys_device_test_src_lib"
-    }
-  ]
-}
diff --git a/cras/client/libcras/TEST_MAPPING b/cras/client/libcras/TEST_MAPPING
deleted file mode 100644
index e8ffe50..0000000
--- a/cras/client/libcras/TEST_MAPPING
+++ /dev/null
@@ -1,13 +0,0 @@
-// Generated by cargo2android.py for tests in Android.bp
-{
-  "presubmit": [
-    {
-      "name": "libcras_host_test_src_libcras",
-      "host": true
-// Presubmit tries to run x86, but we only support 64-bit builds.
-//    },
-//    {
-//      "name": "libcras_device_test_src_libcras"
-    }
-  ]
-}