Do not provide entry point offset in case it doesn't exist

[metthal]

In files like ba0b32b812b8bd25b1481f25e1ab37663611e87c73e9f15f6a9c442a97add916, entry point is set to section which is pure in-memory section and doesn't contain any data on disk. However we try to calculate entry point offset for sections like these while it doesn't make sense because reaching into a file at that offset doesn't lead to anything.

Please make it so that entry point address is first checked for the actual presence on the disk (using section headers) before it is calculated into offset and not provided in such case.