Fix binaryninja function iteration

[github-actions]

closes #142

[mm4rks]

BinaryninjaFrontend._get_address("_1") may return an address to a DataSymbol. Leading to bv.get_function_at_address(<not an address related to function>) to return None.

This is caused by bv.symbols.get("_1", None) returning a list of DataSymbols and FunctionSymbols seemingly corresponding to the "_1" symbol.

However, the symbols_list for "_1" contains multiple FunctionSymbols, where only one is pointing to the correct function (others point to differently named functions).

If we want to go the route of resolving symbols, we could iterate this list and check for correct function names (and correct symbol type).
Or we could get function directly by name, and resolve symbols as a fallback.