NodeSync test for when both petitioner and responder have no blocks

[ronnno]

Description

Added a new test as required in #329 for a scenario when both petitioner (asking node) and responder nodes are at block height 0. Affecting scenarios where two nodes are launched simultaneously for the first time.

• resolves block sync assume always 'start from block 1' #329
• Added harness function verifyMocksConsistently for cases where mocks are expected to Never() do something. This function should be called immediately after verifyMocks which has an Eventually type behavior to be tolerant for some delay before the mocks arrive at the first verified state.
• minor syntactic changes to remove code warnings.

Types of changes

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• Bugfix (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)