Revert "fixup "vfs: rename Vfs::size_t to Vfs::file_size" (sysio adaptations)"

This reverts commit dc5265691fdb92f85259c59accdf450c02eedabd.

Conflicts:
	repos/ports/src/lib/libc_noux/plugin.cc
Revert "fixup "vfs: rename Vfs::size_t to Vfs::file_size""

This reverts commit e9c1b71eda01a353ccb0bafd0100b565b004cc71.

Conflicts:
	repos/ports/src/lib/libc_noux/plugin.cc
fixup "vfs: rename Vfs::size_t to Vfs::file_size"

Fixes #1246