fix tail call optimization in flow_parser.js
fix tail call optimization in flow_parser.js

Summary:
js_of_ocaml doesn't perform tail call optimization in the object property parser, which I think is related to using `let rec ... and ... and ...`.

we don't need to use `and` for this function, and not doing so enables the tail call optimization... ¯\_(ツ)_/¯

Reviewed By: jbrown215

Differential Revision: D12059543

fbshipit-source-id: ccdadb466751f0d8ee8f5faa9dca2eb776e8ec5a

AgentME/flow,facebook/flow,mroch/flow,popham/flow,facebook/flow,jamesgpearce/flow,gabelevi/flow,jamesgpearce/flow,jamesgpearce/flow,samwgoldman/flow,jamesgpearce/flow,mroch/flow,gabelevi/flow,popham/flow,samwgoldman/flow,AgentME/flow,jamesgpearce/flow,facebook/flow,jamesgpearce/flow,popham/flow,samwgoldman/flow,mroch/flow,popham/flow,gabelevi/flow,mroch/flow,samwgoldman/flow,facebook/flow,popham/flow,samwgoldman/flow,samwgoldman/flow,gabelevi/flow,gabelevi/flow,facebook/flow,mroch/flow,jamesgpearce/flow,facebook/flow,popham/flow,AgentME/flow,facebook/flow,gabelevi/flow,popham/flow,mroch/flow,gabelevi/flow,AgentME/flow,samwgoldman/flow,AgentME/flow,mroch/flow