Precached state modified by rerendering

[theogf]

When running export_directory with the cache activated and state "unbaked", it looks like the file.plutostate is modified by rerunning the script once, future reruns do not modify the file.

To reproduce:

• Get a notebook file.jl
• Render it once with Export_baked_state = false and with a Export_cache_dir and get file.html, file.plutostate and some cache/<hash>.plutostate
• Store a copy of file.plutostate.old
• Render it again, the execution states: Loaded from cache, skipping notebook run
• The file.plutostate is now different from file.plutostate.old
• Make another copy file.plutostate.notthatold
• Render again!
• Now file.plutostate is the same as file.plutostate.notthatold

[fonsp]

Love it! Do you still have these statefiles maybe?