It's useful to reproduce different execution problems including executions
stopped because of GAS limit. Satoshi representation is deliberately used,
because that's what is usually found in logs.
Problem: failing part of TestLoad:
```
=== RUN TestLoad/loadgo,_check_signers
cli_test.go:160:
Error Trace: /home/circleci/go/src/github.com/nspcc-dev/neo-go/cli/vm/cli_test.go:160
/home/circleci/go/src/github.com/nspcc-dev/neo-go/cli/vm/cli_test.go:147
/home/circleci/go/src/github.com/nspcc-dev/neo-go/cli/vm/cli_test.go:444
Error: command took too long time
Test: TestLoad/loadgo,_check_signers
```
Solution: split the test into multiple parts to reduce test execution time.
Share parameters parsing code between 'contract invokefunction' and
'vm run' commands. It allows VM CLI to parse more complicated parameter
types including arrays and file-backed bytestrings.