More robust vdbg! macro (#4995)
### Description
I ran into a couple of issues with the vdbg! macro:
* The macro tries to move its parameters within an async block, which
requires everything that's moved to be both `Copy` and `'static` to work
properly. This would break when trying to pass `&obj.property`, where
the reference doesn't have a `'static` lifetime. Instead, I'm adding the
requirement on parameters to impl `ToOwned` so we can ensure the
`'static` lifetime, and creating an owned version of the parameter to
move into the future.
* The `CELL_COUNTERS` thread local could be unset when calling
`.value_debug_format().try_to_string()`, which would panic the thread.
