Update TEST_MAPPING am: bb278c9fe7 am: de4924abd2 am: 4303567ad4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/heck/+/2005840

Change-Id: Ie44df7b5f178f24301211105db3810c6db216496
diff --git a/TEST_MAPPING b/TEST_MAPPING
index af9eb77..e5f5c4c 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -2,6 +2,9 @@
 {
   "imports": [
     {
+      "path": "external/rust/crates/argh"
+    },
+    {
       "path": "external/rust/crates/base64"
     }
   ],