Buck should run packages/flow-dev-tools jest tests
Buck should run packages/flow-dev-tools jest tests

Summary:
We have a few jest tests for packages/flow-dev-tools which I don't think CI is testing

```
$ cd packages/flow-dev-tools
$ FLOW_BIN=`which flow` yarn test
Using Yarn from /data/users/glevi/fbsource/xplat/third-party/yarn/yarn
yarn run v1.17.0-20190429.1820
$ jest
 PASS  src/comment/remove-commentsRunner.test.js
 PASS  src/comment/add-commentsRunner.test.js
 PASS  src/utils/async.test.js
 PASS  src/utils/string.test.js

Test Suites: 4 passed, 4 total
Tests:       4 passed, 4 total
Snapshots:   0 total
Time:        1.518s
Ran all test suites.
Done in 2.04s.
```

Reviewed By: samwgoldman

Differential Revision: D17962438

fbshipit-source-id: aad9edd805d860593f2f16d145d73ee63e9498fb

nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow