Clean up rust_test_host TEST_MAPPING after default update am: ab7dbba14c am: 1e83984d27 am: d4303cb24b

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/proc-macro-error-attr/+/1584352

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I84a1a372e9be1f5eebd40a2526dfe26862c40b28
diff --git a/TEST_MAPPING b/TEST_MAPPING
deleted file mode 100644
index f890bf7..0000000
--- a/TEST_MAPPING
+++ /dev/null
@@ -1,13 +0,0 @@
-// Generated by cargo2android.py for tests in Android.bp
-{
-  "presubmit": [
-    {
-      "host": true,
-      "name": "proc-macro-error-attr_host_test_src_lib"
-    },
-    {
-      "host": true,
-      "name": "structopt-derive_host_test_src_lib"
-    }
-  ]
-}