Revert memfd file sealing for embeded files
Revert memfd file sealing for embeded files

Ideally, we'd seal the embedded SAPI binary using fcntl(). However, in rare
cases, adding the file seals `F_SEAL_SEAL | F_SEAL_SHRINK | F_SEAL_GROW |
F_SEAL_WRITE` results in `EBUSY` errors.

This is likely because of an interaction of `SEAL_WRITE` with pending writes
to the mapped memory region (see `memfd_wait_for_pins()` in Linux'
`mm/memfd.c`). Since `fsync()` is a no-op on memfds, it doesn't help to
ameliorate the problem.

On systems where it is enabled, ksmd might also be a source of pending writes.

PiperOrigin-RevId: 385741435
Change-Id: I21bd6a9039be4b6298774e837ce3628180ed91a8

google/sandboxed-api,google/sandboxed-api,google/sandboxed-api,google/sandboxed-api