libc tests: remove unused features

src/tools/miri/tests/pass-dep/libc/libc-affinity.rs

@@ -1,7 +1,5 @@
 //@only-target: linux freebsd # these are Linux/FreeBSD-specific APIs
 //@compile-flags: -Zmiri-disable-isolation -Zmiri-num-cpus=4
-#![feature(io_error_more)]
-#![feature(pointer_is_aligned_to)]
 
 use std::mem::{size_of, size_of_val};
 

src/tools/miri/tests/pass-dep/libc/libc-fs-permissions.rs

@@ -2,9 +2,6 @@
 //@ignore-host: windows # needs unix PermissionExt
 //@compile-flags: -Zmiri-disable-isolation
 
-#![feature(io_error_more)]
-#![feature(io_error_uncategorized)]
-
 use std::ffi::{CStr, CString};
 use std::mem::MaybeUninit;
 use std::os::unix::ffi::OsStrExt;

src/tools/miri/tests/pass-dep/libc/libc-fs.rs

@@ -1,9 +1,6 @@
 //@ignore-target: windows # no libc
 //@compile-flags: -Zmiri-disable-isolation
 
-#![feature(io_error_more)]
-#![feature(io_error_uncategorized)]
-
 use std::ffi::{CStr, CString, OsString};
 use std::fs::{File, canonicalize, remove_file};
 use std::io::{Error, ErrorKind, Write};

src/tools/miri/tests/pass-dep/libc/libc-misc.rs

@@ -1,7 +1,5 @@
 //@ignore-target: windows # only very limited libc on Windows
 //@compile-flags: -Zmiri-disable-isolation
-#![feature(io_error_more)]
-#![feature(pointer_is_aligned_to)]
 
 use std::mem::transmute;