Ghidra: Skip functions in non-loaded address spaces

For instance, functions that are created for readability by scripts such as
the [Linux syscall resolver](https://github.com/NationalSecurityAgency/ghidra/blob/master/Ghidra/Features/Base/ghidra_scripts/ResolveX86orX64LinuxSyscallsScript.java)
have usually the type `AddressSpace::TYPE_OTHER` and their own namespace
(`syscall` in this case).

For those functions, the address offset will not be accurate and exporting
those functions makes the resulting .BinExport proto unsuitable for BinDiff
("Call graph nodes not sorted").

Drive-by changes:
- Remove `final` in local variables (per Google style guide)
- Replace the use of `java.util.Vector` which performs synchronization. Use
  `java.util.ArrayList` instead.

PiperOrigin-RevId: 373755052
Change-Id: Id38c7cfc95ff9ee7b621ccb432d3fdcac00b4ed5