miri: Remove feature(new_uninit)

Author: workingjubilee

src/tools/miri/tests/fail/data_race/alloc_read_race.rs

@@ -1,7 +1,6 @@
 //@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0 -Zmiri-disable-stacked-borrows
 // Avoid accidental synchronization via address reuse inside `thread::spawn`.
 //@compile-flags: -Zmiri-address-reuse-cross-thread-rate=0
-#![feature(new_uninit)]
 
 use std::mem::MaybeUninit;
 use std::ptr::null_mut;

src/tools/miri/tests/fail/data_race/alloc_write_race.rs

@@ -1,7 +1,6 @@
 //@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0 -Zmiri-disable-stacked-borrows
 // Avoid accidental synchronization via address reuse inside `thread::spawn`.
 //@compile-flags: -Zmiri-address-reuse-cross-thread-rate=0
-#![feature(new_uninit)]
 
 use std::ptr::null_mut;
 use std::sync::atomic::{AtomicPtr, Ordering};

src/tools/miri/tests/pass/rc.rs

@@ -1,7 +1,6 @@
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@compile-flags: -Zmiri-strict-provenance
-#![feature(new_uninit)]
 #![feature(get_mut_unchecked)]
 #![allow(ambiguous_wide_pointer_comparisons)]
 

src/tools/miri/tests/pass/slices.rs

@@ -1,7 +1,6 @@
 //@revisions: stack tree
 //@[tree]compile-flags: -Zmiri-tree-borrows
 //@compile-flags: -Zmiri-strict-provenance
-#![feature(new_uninit)]
 #![feature(slice_as_chunks)]
 #![feature(slice_partition_dedup)]
 #![feature(layout_for_ptr)]