Make Parser skip files it's seen already. (#5048)
Make Parser skip files it's seen already. (#5048)

The use case is so we can batch compile a bunch of schemas, some which can depend on each other, without caring about their order.
royalharsh/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,alexames/flatbuffers,stewartmiles/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,google/flatbuffers,google/flatbuffers,DavadDi/flatbuffers,hgl888/flatbuffers,evolutional/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,hgl888/flatbuffers,google/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,royalharsh/flatbuffers,royalharsh/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,google/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,google/flatbuffers,pjulien/flatbuffers,alexames/flatbuffers,google/flatbuffers,hgl888/flatbuffers,google/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,royalharsh/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,royalharsh/flatbuffers,pjulien/flatbuffers,hgl888/flatbuffers,pjulien/flatbuffers,hgl888/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,evolutional/flatbuffers,google/flatbuffers,hgl888/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,google/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,DavadDi/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,royalharsh/flatbuffers,pjulien/flatbuffers,google/flatbuffers,google/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers