ut: fix HF_Echidna unit tests

[shargon]

Description

My bad, the previous code also checks in the executable folder.

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Not changed

Test Configuration:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[Jim8y]

Nice work @shargon

[AnnaShaleva]

Otherwise LGTM.

[AnnaShaleva]

My primary concern here is that this code should be compatible with the old behaviour of neo-cli binary for production usage (default config.json file from the neo-cli binary dir will be used). From what I see, it's OK, but we'd better recheck.