Add a temporary target to help with the migration to gn artifacs.

We'll save the file to the new and old locations while we transition
from recipes generated artifacts to gn generated ones. Once we finish
that implementation we will start standardizing artifact names and
location.

Bug: flutter/flutter#105351

Author: godofredoc

sky/dist/BUILD.gn

@@ -37,6 +37,19 @@ if (is_android) {
     ]
     deps = [ ":sky_engine" ]
   }
+
+  zip_bundle("zip_old_location") {
+    # TODO godofredoc: remove after we migrate the tool to use the new location.
+    # Bug: https://github.com/flutter/flutter/issues/105351
+    output = "sky_engine.zip"
+    files = [
+      {
+        source = "$root_build_dir/dist/packages/sky_engine"
+        destination = "sky_engine"
+      },
+    ]
+    deps = [ ":sky_engine" ]
+  }
 }
 
 group("dist") {