SC: Pretty print sync call consoles from contract in call hierarchy

[linh2931]

This PR implements pretty print sync call consoles from contract in call hierarchy.

Resolves #1579

cleos support of pretty printing and call traces is tracked by #1628.

Example of both caller and callee have consoles:

[(caller,basictest)->caller]: CONSOLE OUTPUT BEGIN =====================
Before calling sync call basictest
[caller->(callee,basictest)]: CALL BEGIN ======
I am basictest from sync_callee
[caller->(callee,basictest)]: CALL END   ======
After returned from basictest
[(caller,basictest)->caller]: CONSOLE OUTPUT END   =====================

Example of only callee has console:

[(caller,callernocnsl)->caller]: CONSOLE OUTPUT BEGIN =====================
[caller->(callee,basictest)]: CALL BEGIN ======
I am basictest from sync_callee
[caller->(callee,basictest)]: CALL END   ======
[(caller,callernocnsl)->caller]: CONSOLE OUTPUT END   =====================

Example of only caller has console:

[(caller,calleenocnsl)->caller]: CONSOLE OUTPUT BEGIN =====================
Before making sync call. After returned from sync call.
[(caller,calleenocnsl)->caller]: CONSOLE OUTPUT END   =====================

[heifner]

Could avoid this copy by using output from the start and append as you go.

[linh2931]

If we use output from the start and append as we go, we will append header at the beginning. Then we need to use "if output is equal to header" at the end to determine if the console has anything, because we don't want to output anything if console (including sync calls') is empty.

[heifner]

You could track that via a bool, but doesn't really matter.