add flow-parser libdef in flow-dev-tools
add flow-parser libdef in flow-dev-tools

Summary:
allows running `flow packages/flow-dev-tools` without first (or successfully) compiling flow_parser.js. if you don't have opam set up, building flow_parser fails when running `yarn`, but that doesn't need to stop flow from working.

Changelog: [internal]

Reviewed By: SamChou19815

Differential Revision: D39098163

fbshipit-source-id: 0046cf1396bf37afcb0ff234dfff8080a0e42cba

mroch/flow,mroch/flow,facebook/flow,mroch/flow,mroch/flow,facebook/flow,facebook/flow,facebook/flow,facebook/flow,mroch/flow,mroch/flow,facebook/flow,mroch/flow,facebook/flow