Rename 'doCheckContract' into 'parseContractAndReportErrors',
emphasizing that it works with definitely call to 'contract' from
stdlib.
In particular, it means that it should either return non-null
value or report some errors.
Note that this commit doesn't change behavior of this code (modulo cases
when something in 'parseContract' throws exception), but just refactors
the code to be more clear and easy to reason about.
Dmitry Savvinov
339c55505a