test/simd: add test for issue 77582

This addresses post-merge feedback from Cherry regarding CL 745460.

Updates #77582

Change-Id: I1165b8f499d2381b3d45e4a14f9d052d947b33c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/748760
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

test/simd/issue77582.go

@@ -1,29 +1,25 @@
+// compile
+
+//go:build goexperiment.simd && amd64
+
 // Copyright 2026 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.simd && amd64
-
-package ssa
+package p
 
 import (
-	"testing"
-
-	"cmd/compile/internal/archsimd"
+	"simd/archsimd"
 )
 
-func TestVPTERNLOGDPanic(t *testing.T) {
-	if !archsimd.X86.AVX512() {
-		t.Skip("Test only applies to AVX512")
-	}
-
+func vpternlogdPanic() {
 	resultsMask := archsimd.Mask64x8{}
 	a := archsimd.Mask64x8FromBits(0xFF)
 	b := archsimd.Float64x8{}.Less(archsimd.Float64x8{})
 
 	for i := 0; i < 1; i++ {
 		resultsMask = a.Or(b).Or(resultsMask)
-		// This nested logic triggered the panic
+		// This nested logic triggered the panic in CL 745460
 		_ = resultsMask.And(resultsMask.And(archsimd.Mask64x8{}))
 	}
 }