message: [bench] Avoid function call arguments which are pointers to uninitialized values
  This is a port of Core
diff: @@ -20,7 +20,7 @@ static void DeserializeBlockTest(benchmark::State& state)
  CDataStream stream((const char*)block_bench::block413567,
  (const char*)&block_bench::block413567[sizeof(block_bench::block413567)],
  SER_NETWORK, PROTOCOL_VERSION);
  - char a;
  + char a = '\0';
  stream.write(&a, 1); // Prevent compaction
  while (state.KeepRunning()) {
  @@ -35,7 +35,7 @@ static void DeserializeAndCheckBlockTest(benchmark::State& state)
  CDataStream stream((const char*)block_bench::block413567,
  (const char*)&block_bench::block413567[sizeof(block_bench::block413567)],
  SER_NETWORK, PROTOCOL_VERSION);
  - char a;
  + char a = '\0';
  stream.write(&a, 1); // Prevent compaction
  SelectParams(CBaseChainParams::MAIN);
  