src,lib: fix assert when `Error.prepareStackTrace` not overridden
Refs https://github.com/nodejs/node/pull/23926
Fixes an issue caused when embedders choose to set up the v8::Isolate
without a prepareStackTrace callback. In this event, several assert
methods stop working because stack trace formatting relies on a SafeWeakMap
that's only populated in the overridden prepareStackTrace
callback.
Fix this by exposing override status under getEmbedderOptions
and falling back to the default implementation of Error.prepareStackTrace
if it's not been overridden.