Skip building libfs_avb unittest for Mac

Bug: 117960205
Test: m libfs_avb_host_unittest
Change-Id: Ib53efe3e36a3f70134b2431c2c0bfed52fdd3df6
diff --git a/fs_mgr/libfs_avb/tests/Android.bp b/fs_mgr/libfs_avb/tests/Android.bp
index 4c02237..24e1d76 100644
--- a/fs_mgr/libfs_avb/tests/Android.bp
+++ b/fs_mgr/libfs_avb/tests/Android.bp
@@ -32,4 +32,9 @@
     srcs: [
         "fs_avb_unittest_util.cpp",
     ],
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
 }