Lua library: fix vtable reuse. (#5214)
Lua library: fix vtable reuse. (#5214)

Fixed a bug that prevented vtable reuse during buffer construction in the lua library.

Also fixed a bug in vtable equality check that was revealed after the first fix.
stewartmiles/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,stewartmiles/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,hgl888/flatbuffers,alexames/flatbuffers,hgl888/flatbuffers,google/flatbuffers,pjulien/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,google/flatbuffers,hgl888/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,hgl888/flatbuffers,pjulien/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,pjulien/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,google/flatbuffers,stewartmiles/flatbuffers,evolutional/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,google/flatbuffers,stewartmiles/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,stewartmiles/flatbuffers,hgl888/flatbuffers,google/flatbuffers,pjulien/flatbuffers,DavadDi/flatbuffers,pjulien/flatbuffers,evolutional/flatbuffers,google/flatbuffers,google/flatbuffers,DavadDi/flatbuffers,pjulien/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,evolutional/flatbuffers,pjulien/flatbuffers,DavadDi/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,pjulien/flatbuffers,stewartmiles/flatbuffers,google/flatbuffers,google/flatbuffers,evolutional/flatbuffers,google/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,hgl888/flatbuffers,DavadDi/flatbuffers