Don't expect specific instructions for _mm256_set_pd/_mm_set_ps

These don't correspond to specific instructions and will produce
different instructions on x86/x86_64 based on ABI details.

Author: nikic

crates/core_arch/src/x86/avx.rs

@@ -2426,7 +2426,6 @@ pub const fn _mm256_setzero_si256() -> __m256i {
 #[inline]
 #[target_feature(enable = "avx")]
 // This intrinsic has no corresponding instruction.
-#[cfg_attr(test, assert_instr(vinsertf128))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
 #[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
 pub const fn _mm256_set_pd(a: f64, b: f64, c: f64, d: f64) -> __m256d {

crates/core_arch/src/x86/sse.rs

@@ -968,7 +968,7 @@ pub const fn _mm_set_ps1(a: f32) -> __m128 {
 /// [Intel's documentation](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_set_ps)
 #[inline]
 #[target_feature(enable = "sse")]
-#[cfg_attr(test, assert_instr(unpcklps))]
+// This intrinsic has no corresponding instruction.
 #[stable(feature = "simd_x86", since = "1.27.0")]
 #[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
 pub const fn _mm_set_ps(a: f32, b: f32, c: f32, d: f32) -> __m128 {