fix Flow typing for OSS

Summary:
Add ignores for these requires, some of them mistakenly removed by da3424c929.

```
yarn flow
```

CircleCI should be green again.
Closes https://github.com/facebook/react-native/pull/18021

Differential Revision: D7025304

Pulled By: jeanlauliac

fbshipit-source-id: 731232093ae3ab39b3eff6fb2004ff4e7090d5ae

jest/preprocessor.js

@@ -30,6 +30,7 @@ const nodeOptions = babelRegisterOnly.config([nodeFiles]);
 
 babelRegisterOnly([]);
 
+/* $FlowFixMe(site=react_native_oss) */
 const transformer = require('metro/src/transformer.js');
 module.exports = {
   process(src/*: string*/, file/*: string*/) {

local-cli/bundle/buildBundle.js

@@ -10,12 +10,16 @@
 'use strict';
 
 const log = require('../util/log').out('bundle');
+/* $FlowFixMe(site=react_native_oss) */
 const Server = require('metro/src/Server');
 const {Terminal} = require('metro-core');
+/* $FlowFixMe(site=react_native_oss) */
 const TerminalReporter = require('metro/src/lib/TerminalReporter');
+/* $FlowFixMe(site=react_native_oss) */
 const TransformCaching = require('metro/src/lib/TransformCaching');
 
 const {defaults} = require('metro');
+/* $FlowFixMe(site=react_native_oss) */
 const outputBundle = require('metro/src/shared/output/bundle');
 const path = require('path');
 const saveAssets = require('./saveAssets');

local-cli/bundle/types.flow.js

@@ -8,4 +8,5 @@
  */
 'use strict';
 
+/* $FlowFixMe(site=react_native_oss) */
 export type {OutputOptions, RequestOptions} from 'metro/src/shared/types.flow';

local-cli/server/runServer.js

@@ -43,11 +43,14 @@ const statusPageMiddleware = require('./middleware/statusPageMiddleware.js');
 const systraceProfileMiddleware = require('./middleware/systraceProfileMiddleware.js');
 const webSocketProxy = require('./util/webSocketProxy.js');
 
+/* $FlowFixMe(site=react_native_oss) */
 const TransformCaching = require('metro/src/lib/TransformCaching');
 
 const {ASSET_REGISTRY_PATH} = require('../core/Constants');
 
+/* $FlowFixMe(site=react_native_oss) */
 import type {ConfigT} from 'metro';
+/* $FlowFixMe(site=react_native_oss) */
 import type {Reporter} from 'metro/src/lib/reporting';
 
 export type Args = {|