Implement GT-2845 (Memory API to preserve imported program's original bytes)

[JayFoxRox]

Ghidra supports loading of the original file now (from "Ghidra v9.1 (September 2019)" changelog):

Memory. Added new API to preserve imported program's original bytes and how they map to memory blocks. (GT-2845)

This probably means the importer no longer has to slice the file into different sections, thereby making it nearly impossible to reach bytes which the importer didn't support at the time.

Someone should look into this.

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For some reference changes also look at this:

https://github.com/NationalSecurityAgency/ghidra/search?q=%22gt-2845%22&type=Commits