tests/fuzzers: update fuzzers to be based on go-native fuzzing (#28352)

This change modifies the fuzzers to use the native golang fuzzing framework instead of go-fuzz

tests/fuzzers/difficulty/difficulty_test.go

@@ -0,0 +1,25 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package difficulty
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data []byte) {
+		fuzz(data)
+	})
+}