run: disable network tests on rpi

No working network driver so far.
fixup "vfs: rename Vfs::size_t to Vfs::file_size" (sysio adaptations)
fixup "vfs: rename Vfs::size_t to Vfs::file_size"

Fixes #1246
fixup "run: disable network tests on rpi" (lwip)

No working network support so far.
fixup "run: disable network tests on rpi" (netcat)

No working network support so far.