correct vpdpbusd asserts in miri

in a24022a we changed the argument types to be more accurate, and now the miri asserts on the simd type/size need to reflect that

Author: folkertdev

src/tools/miri/src/shims/x86/avx512.rs

@@ -188,12 +188,12 @@ fn vpdpbusd<'tcx>(
     let (b, b_len) = ecx.project_to_simd(b)?;
     let (dest, dest_len) = ecx.project_to_simd(dest)?;
 
-    // fn vpdpbusd(src: i32x16, a: i32x16, b: i32x16) -> i32x16;
-    // fn vpdpbusd256(src: i32x8, a: i32x8, b: i32x8) -> i32x8;
-    // fn vpdpbusd128(src: i32x4, a: i32x4, b: i32x4) -> i32x4;
+    // fn vpdpbusd(src: i32x16, a: u8x64, b: i8x64) -> i32x16;
+    // fn vpdpbusd256(src: i32x8, a: u8x32, b: i8x32) -> i32x8;
+    // fn vpdpbusd128(src: i32x4, a: u8x16, b: i8x16) -> i32x4;
     assert_eq!(dest_len, src_len);
-    assert_eq!(dest_len, a_len);
-    assert_eq!(dest_len, b_len);
+    assert_eq!(a_len, dest_len / 4);
+    assert_eq!(a_len, b_len);
 
     for i in 0..dest_len {
         let src = ecx.read_scalar(&ecx.project_index(&src, i)?)?.to_i32()?;