feat(arch): the vector-length arithmetic pseudo group

Assisted-by: GLM 5.3 Flash

asm/extension_test.go

@@ -346,6 +346,9 @@ func TestExtensionNamesARM64(t *testing.T) {
 		"ZCMPHI",
 		"ZCMPHS",
 		"ZCMPNE",
+		"ADDPL",
+		"ADDVL",
+		"RDVL",
 		"ZLD2B",
 		"ZLD2D",
 		"ZLD2H",
@@ -488,7 +491,7 @@ func TestExtensionNamesARM64(t *testing.T) {
 	if strings.Join(got, ",") != strings.Join(want, ",") {
 		t.Errorf("ExtensionNames(ARM64) = %v, want %v", got, want)
 	}
-	if n := len(arch.Extensions(arch.ARM64)); n != 497 {
-		t.Errorf("the family registers %d instructions, want 497", n)
+	if n := len(arch.Extensions(arch.ARM64)); n != 500 {
+		t.Errorf("the family registers %d instructions, want 500", n)
 	}
 }