Add unit test for drag handler enable/disable bug (#4387)
Add unit test for drag handler enable/disable bug (#4387)

AP-whitehat/Leaflet,msiadak/Leaflet,Leaflet/Leaflet,Ubisense/Leaflet,fab1an/Leaflet,davojta/Leaflet,scaddenp/Leaflet,msiadak/Leaflet,hyperknot/Leaflet,frogcat/Leaflet,CapeSepias/Leaflet,hyperknot/Leaflet,rlugojr/Leaflet,iZucken/Leaflet,tsantacruz/RotationalMarker,fab1an/Leaflet,davojta/Leaflet,iOffice/Leaflet,akrzyzanowskino/TeamSE,scaddenp/Leaflet,jasonoverland/Leaflet,iOffice/Leaflet,akrzyzanowskino/TeamSE,codeator/Leaflet,Neorth/Leaflet,geoloep/Leaflet,Leaflet/Leaflet,AP-whitehat/Leaflet,rlugojr/Leaflet,davojta/Leaflet,tsantacruz/RotationalMarker,Ubisense/Leaflet,tsantacruz/RotationalMarker,iZucken/Leaflet,frogcat/Leaflet,CapeSepias/Leaflet,geoloep/Leaflet,msiadak/Leaflet,brah/Leaflet,bbecquet/Leaflet,brah/Leaflet,fab1an/Leaflet,scaddenp/Leaflet,Trufi/Leaflet,hyperknot/Leaflet,Leaflet/Leaflet,rlugojr/Leaflet,codeator/Leaflet,stefanocudini/Leaflet,w8r/Leaflet,sisou/Leaflet,jasonoverland/Leaflet,stefanocudini/Leaflet,Trufi/Leaflet,iOffice/Leaflet,codeator/Leaflet,iZucken/Leaflet,bbecquet/Leaflet,sisou/Leaflet,stefanocudini/Leaflet,Ubisense/Leaflet,jasonoverland/Leaflet,bbecquet/Leaflet,w8r/Leaflet,Neorth/Leaflet,frogcat/Leaflet,w8r/Leaflet,CapeSepias/Leaflet,Trufi/Leaflet,AP-whitehat/Leaflet,akrzyzanowskino/TeamSE,geoloep/Leaflet,Neorth/Leaflet,brah/Leaflet,sisou/Leaflet