[system image] Migrate libc-tests to pkgfs

Change-Id: I246d5dcc11ac97d7ba3d011c052d85be3870acf7
Tested: affected tests ran successfully out of pkgfs
Bug: PKG-46
diff --git a/BUILD.gn b/BUILD.gn
index b4e485d..79c9fe3 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -59,7 +59,6 @@
 
 package("libc-tests") {
   testonly = true
-  deprecated_system_image = true
 
   deps = [
     ":libc-large-tests",