[native] Buffer overflow bug writting to `output_stream`

[smlu]

In output_stream::push no check for buffer bounds can lead to buffer overrun.

I have large test sets where contract code invokes eosio::print* functions many times and the global std_out is not cleared through tests. Eventually the std_out overwrites std_err leading to segmentation fault.

[stephenpdeos]

Prioritizing for a patch release after 3.1

[ericpassmore]

closed in AntelopeIO/CDT