It was regressed in 2 ways from the merge of #6250:
 * it was not being enabled by default when the target OS is native.
 * we were testing the libfoo.so file path existence with bogus format
   string ('{}' instead of '{s}') and so it ended up being something
   like "libstd.HashMap(K,V,...).Entry.so" instead of "libfoo.so". Using
   {} rather than {s} is a footgun, be careful!

Previous functionality is now restored.

closes #6523