tests/fuzzers/les: add fuzzer for les server handler (#22282)

* les: refactored server handler

* tests/fuzzers/les: add fuzzer for les server handler

* tests, les: update les fuzzer

tests: update les fuzzer

tests/fuzzer/les: release resources

tests/fuzzer/les: pre-initialize all resources

* les: refactored server handler and fuzzer

Co-authored-by: rjl493456442 <garyrong0905@gmail.com>

les/test_helper.go

@@ -594,3 +594,7 @@ func newClientServerEnv(t *testing.T, blocks int, protocol int, callback indexer
 	}
 	return s, c, teardown
 }
+
+func NewFuzzerPeer(version int) *clientPeer {
+	return newClientPeer(version, 0, p2p.NewPeer(enode.ID{}, "", nil), nil)
+}