Idea: Fall back to php's json_decode internally in simdjson_decode for json length > 4 GiB

[TysonAndre]

(instead of throwing SimdJsonException for the capacity error)

simdjson_decode is meant to have indistinguishable behavior from json_decode apart from error codes/classes/messages, so this should be safe

• Use the JsonException message and a distinct SIMDJSON_ERR* error code

Libraries using simdjson_decode may be forced to add extra error handling if they expect to be used for JSON > 4 GiB by any application using them. It'd be more convenient to avoid that.

Low priority compared to other tasks due to most php installations having max upload sizes