Fix problems on running Jest with React native v0.56

The combination of Jest and React native version 0.56 may have some problems and these steps should be fix those problems.

yarn test
yarn run v1.7.0
$ jest
 FAIL  __tests__/timeline_form_screen_test.js
  ● Test suite failed to run

  Plugin 0 specified in "/ReactNative/AppName/node_modules/babel-preset-react-native/index.js" provided an invalid property of "default" (While processing preset: "/ReactNative/AppName/node_modules/babel-preset-react-native/index.js")

      at Plugin.init (node_modules/babel-core/lib/transformation/plugin.js:131:13)
      at Function.normalisePlugin (node_modules/babel-core/lib/transformation/file/options/option-manager.js:152:12)
      at node_modules/babel-core/lib/transformation/file/options/option-manager.js:184:30
          at Array.map (<anonymous>)
      at Function.normalisePlugins (node_modules/babel-core/lib/transformation/file/options/option-manager.js:158:20)
      at OptionManager.mergeOptions (node_modules/babel-core/lib/transformation/file/options/option-manager.js:234:36)
      at node_modules/babel-core/lib/transformation/file/options/option-manager.js:265:14
      at node_modules/babel-core/lib/transformation/file/options/option-manager.js:323:22
          at Array.map (<anonymous>)
      at OptionManager.resolvePresets (node_modules/babel-core/lib/transformation/file/options/option-manager.js:275:20)

If you got erro above, rename .babelrc to .babel.config.js on your React Native project root and will fix the error.

However still may have another error.

 /ReactNative/AppName/__tests__/component_test.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import React from 'react';
                                                                                                    ^^^^^

    SyntaxError: Unexpected identifier

      at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:403:17)

Modify package.json like below.

"jest": {
    "preset": "react-native"
  }

to

"jest": {
    "preset": "react-native",
    "transform": {
      "^.+\\.js$": "<rootDir>/node_modules/react-native/jest/preprocessor.js"
    }
  }

Then it will fix the error.