eosjs return codes

[ericpassmore]

Investigate correct return code for --return-failure-trace ture and transaction failed to speculatively execute.

As of Leap 3, defaults to --return-failure-trace true which means that automation which depends on eosjs to return a non-zero value on transaction failure will instead need to parse the traces or use option --return-failure-trace false.

Update to parse transaction trace and return a non-zero error code when the trace includes an exception indicating the transaction failed to speculatively execute.