Clean up rust_test_host TEST_MAPPING after default update am: b1005cf632

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/libz-sys/+/1584585

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ib70bd53ddd04acbb1ab25f9e16095542e208b8d2
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 48c70d6..030396e 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -2,10 +2,6 @@
 {
   "presubmit": [
     {
-      "host": true,
-      "name": "libz-sys_host_test_src_lib"
-    },
-    {
       "name": "libz-sys_device_test_src_lib"
     }
   ]