message: add some code for test db
diff: @@ -10,9 +10,66 @@ test = N(b'test')
  def test_call_wasm_function():
  eoslib.call_wasm_function(N('test2'), N(b'hello'), [1,2])
  +def test_rw_db():
  + keys = struct.pack('Q', N('currency'))
  + values = bytes(16)
  + eos = N('eos')
  + ret = eoslib.load(eos, eos, N('test'), keys, 0, 0, values)
  + print('+++++++eoslib.load return:',ret)
  + print(values)
  + results = struct.unpack('QQ', values)
  + print(results)
  +
  + print('--------------------------------')
  + keys = struct.pack('Q', N('currency'))
  + values = struct.pack('QQ', 77, 88)
  + ret = eoslib.store(test, eos, N('test'), keys, 0, values)
  + print('++++++++eoslib.store return:',ret)
  +
  + values = bytes(16)
  + ret = eoslib.load(test, eos, N('test'), keys, 0, 0, values)
  + print('+++++++eoslib.load return:',ret)
  + print(values)
  + results = struct.unpack('QQ', values)
  + print(results)
  +
  + print('--------------------------------')
  +
  + keys = struct.pack('Q', N('currency'))
  + values = struct.pack('QQ', 44, 33)
  + ret = eoslib.store(test, test, N('test'), keys, 0, values)
  + print('++++++++eoslib.store return:',ret)
  +
  + values = bytes(16)
  + ret = eoslib.load(test, test, N('test'), keys, 0, 0, values)
  + print('+++++++eoslib.load return:',ret)
  + print(values)
  + results = struct.unpack('QQ', values)
  + print(results)
  +
  +
  def test_db1():
  msg = eoslib.readMessage()
  print(len(msg))
  + test = N(b'eos')
  + result = int.from_bytes(msg[:8], 'little')
  + size = msg[8]
  + for i in range(size):
  + result = int.from_bytes(msg[9 + i * 8:9 + i * 8 + 8], 'little')
  + print(result)
  +
  + keys = msg[:8]
  + values = msg[8:]
  + eoslib.store(test, test, test, keys, 0, values)
  + keys = msg[:8]
  + values = msg[8:]
  + eoslib.load(test, test, test, keys, 0, 0, values)
  + print(values)
  +
  +def test_db2():
  + msg = eoslib.readMessage()
  + print(len(msg))
  + test = N(b'eos')
  result = int.from_bytes(msg[:8], 'little')
  size = msg[8]
  for i in range(size):
  @@ -159,7 +216,7 @@ def apply(code, action):
  to_ = result[1]
  amount = result[2]
  elif action == N(b'test'):
  - test_db2()
  + test_rw_db()
  elif action == N(b'testdb'):
  test_db()
  elif action == N(b'callwasm'):
  