Move AutoGC into EmuFs.
Remove EmuFs and EmuFile tags, since they're not really used.
Rename emufs.h/.cc to EmuFs.h/.cc.
Rename vm.h/.cc to AddressSpace.cc/.h.
Remove iterator_action since it's always CONTINUE.
Move /proc/<pid>/maps iterator from being exposed in util.h to be internal to AddressSpace.cc.
Remove unused size_bytes.
Switch mapped_segment_info::name to std::string.
Remove unused NUM_MAX_MAPS
Remove register-printing functions from utils.h.
Remove get_ipc_command from util.h.
Rename ScopedOpen to ScopedFd and move it to its own header file.
Make create_shmem_segment/resize_shmem_segment use ScopedFd.
Switch EmuFile::fd() to return the ScopedFd.
Use ScopedFd to read auxv.
Use ScopedFd in exec_file_supported.
Use ScopedFd in check_performance_settings.
Switch CompressedReader to use ScopedFd.
Switch CompressedWriter to ScopedFd.
Switch AddressSpace::child_mem_fd to use ScopedFd.