refactor: move test.php into testdata folder

internal/php8/php8_bench_test.go

@@ -2,6 +2,7 @@ package php8_test
 
 import (
 	"io/ioutil"
+	"path/filepath"
 	"testing"
 
 	"github.com/VKCOM/php-parser/internal/php8"
@@ -10,10 +11,9 @@ import (
 )
 
 func BenchmarkPhp8(b *testing.B) {
-	src, err := ioutil.ReadFile("test.php")
-
+	src, err := ioutil.ReadFile(filepath.Join("testdata", "test.php"))
 	if err != nil {
-		b.Fatal("can not read test.php: " + err.Error())
+		b.Fatal("can not read testdata/test.php: " + err.Error())
 	}
 
 	for n := 0; n < b.N; n++ {