Rollup merge of #138940 - sayantn:stabilize-avx512, r=Amanieu,traviscross

Stabilize the avx512 target features

This PR stabilizes the AVX512 target features - see [this comment](rust-lang/rust#111137 (comment)).

Tracking Issue - #44839

The target feature UI tests have been changed to `x87` (chosen because this is very unlikely to stablize ever, please comment if some other feature will be better)

related: #111137

Author: fmease

tests/pass/shims/x86/intrinsics-x86-aes-vaes.rs

@@ -2,7 +2,7 @@
 //@only-target: x86_64 i686
 //@compile-flags: -C target-feature=+aes,+vaes,+avx512f
 
-#![feature(avx512_target_feature, stdarch_x86_avx512)]
+#![feature(stdarch_x86_avx512)]
 
 use core::mem::transmute;
 #[cfg(target_arch = "x86")]

tests/pass/shims/x86/intrinsics-x86-avx512.rs

@@ -2,7 +2,6 @@
 //@only-target: x86_64 i686
 //@compile-flags: -C target-feature=+avx512f,+avx512vl,+avx512bitalg,+avx512vpopcntdq
 
-#![feature(avx512_target_feature)]
 #![feature(stdarch_x86_avx512)]
 
 #[cfg(target_arch = "x86")]

tests/pass/shims/x86/intrinsics-x86-gfni.rs

@@ -6,7 +6,6 @@
 // be interpreted as integers; signedness does not make sense for them, but
 // __mXXXi happens to be defined in terms of signed integers.
 #![allow(overflowing_literals)]
-#![feature(avx512_target_feature)]
 #![feature(stdarch_x86_avx512)]
 
 #[cfg(target_arch = "x86")]

tests/pass/shims/x86/intrinsics-x86-vpclmulqdq.rs

@@ -8,7 +8,6 @@
 // be interpreted as integers; signedness does not make sense for them, but
 // __mXXXi happens to be defined in terms of signed integers.
 #![allow(overflowing_literals)]
-#![feature(avx512_target_feature)]
 #![feature(stdarch_x86_avx512)]
 
 #[cfg(target_arch = "x86")]