[scudo] Always zero on linux even if the memory cannot be released. (#167788) If a caller has locked memory, then the madvise call will fail. In that case, zero the memory so that we don't return non-zeroed memory for calloc calls since we thought the memory had been released. GitOrigin-RevId: 3e28992b304a0c5e3d5690b7bb0827dee02c3af8