[fake-bti] Remove unittest dependency.

ZX-4569 #done

Change-Id: Icdb375aea8e1d738d3315e4cac0453d95ab63e28
diff --git a/zircon/system/dev/lib/fake-bti/BUILD.gn b/zircon/system/dev/lib/fake-bti/BUILD.gn
index 7ec324b..b629a9b 100644
--- a/zircon/system/dev/lib/fake-bti/BUILD.gn
+++ b/zircon/system/dev/lib/fake-bti/BUILD.gn
@@ -12,7 +12,7 @@
   ]
   deps = [
     "$zx/system/ulib/fbl",
-    "$zx/system/ulib/unittest",
+    "$zx/system/ulib/fdio",
     "$zx/system/ulib/zircon",
     "$zx/system/ulib/zx",
   ]