Add libbpf to hwasan-postsubmit am: ae6cd3345b am: 56923eda9a am: 34977b38c2

Original change: https://android-review.googlesource.com/c/platform/external/libbpf/+/2032729

Change-Id: I9c3d1086bb051a50a907240f69fa9b8b857d89c9
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 90892fe..b6a940b 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -3,5 +3,10 @@
     {
       "name": "libbpf_load_test"
     }
+  ],
+  "hwasan-postsubmit": [
+    {
+      "name": "libbpf_load_test"
+    }
   ]
 }