var_export on resource compatibility
Summary:
`var_export(resource)` on a `resource` returns `NULL` in PHP 5/7. We returned
an empty `array`. https://3v4l.org/EZSmE
Let's be compatible.
From php.net docs for `var_export`
> Variables of type resource couldn't be exported by this function.
There are a few different ways I think I could have gone here; I chose the way
with hopefully the most minimal impact to the variable serialization process.
Reviewed By: markw65
Differential Revision:
D2798281
fb-gh-sync-id:
827dd35f865401d07ed9b3ef826bac066add1a2e