custom_sharding.py: Fix correct verification of number of shard_references per tablet type.
custom_sharding.py: Fix correct verification of number of shard_references per tablet type.

The order of the map ("master", "replica", "rdonly") can change, so we cannot compare indexes and must check each type explicitly.
sougou/vitess,aaijazi/vitess,AndyDiamondstein/vitess,HubSpot/vitess,dumbunny/vitess,tinyspeck/vitess,rnavarro/vitess,pivanof/vitess,pivanof/vitess,mahak/vitess,AndyDiamondstein/vitess,mapbased/vitess,mahak/vitess,pivanof/vitess,rnavarro/vitess,aaijazi/vitess,enisoc/vitess,dcadevil/vitess,tinyspeck/vitess,mattharden/vitess,pivanof/vitess,alainjobart/vitess,dcadevil/vitess,guokeno0/vitess,mahak/vitess,mapbased/vitess,sougou/vitess,mapbased/vitess,tirsen/vitess,tirsen/vitess,applift/vitess,mattharden/vitess,AndyDiamondstein/vitess,alainjobart/vitess,tinyspeck/vitess,HubSpot/vitess,mattharden/vitess,pivanof/vitess,tirsen/vitess,vitessio/vitess,vitessio/vitess,guokeno0/vitess,rnavarro/vitess,mattharden/vitess,tirsen/vitess,erzel/vitess,applift/vitess,mattharden/vitess,mapbased/vitess,erzel/vitess,davygeek/vitess,guokeno0/vitess,applift/vitess,sougou/vitess,dcadevil/vitess,enisoc/vitess,AndyDiamondstein/vitess,guokeno0/vitess,dcadevil/vitess,mapbased/vitess,rnavarro/vitess,sougou/vitess,guokeno0/vitess,mahak/vitess,mattharden/vitess,dcadevil/vitess,HubSpot/vitess,mattharden/vitess,sougou/vitess,dumbunny/vitess,tirsen/vitess,HubSpot/vitess,guokeno0/vitess,erzel/vitess,alainjobart/vitess,dumbunny/vitess,AndyDiamondstein/vitess,erzel/vitess,dumbunny/vitess,pivanof/vitess,HubSpot/vitess,guokeno0/vitess,tinyspeck/vitess,erzel/vitess,davygeek/vitess,dumbunny/vitess,pivanof/vitess,enisoc/vitess,dumbunny/vitess,dcadevil/vitess,applift/vitess,alainjobart/vitess,tinyspeck/vitess,mapbased/vitess,vitessio/vitess,mahak/vitess,HubSpot/vitess,aaijazi/vitess,guokeno0/vitess,erzel/vitess,erzel/vitess,aaijazi/vitess,mattharden/vitess,rnavarro/vitess,tirsen/vitess,mattharden/vitess,vitessio/vitess,enisoc/vitess,mapbased/vitess,alainjobart/vitess,applift/vitess,applift/vitess,erzel/vitess,davygeek/vitess,guokeno0/vitess,davygeek/vitess,alainjobart/vitess,mapbased/vitess,AndyDiamondstein/vitess,erzel/vitess,rnavarro/vitess,AndyDiamondstein/vitess,pivanof/vitess,aaijazi/vitess,dumbunny/vitess,HubSpot/vitess,tirsen/vitess,dumbunny/vitess,aaijazi/vitess,dcadevil/vitess,rnavarro/vitess,alainjobart/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,enisoc/vitess,alainjobart/vitess,aaijazi/vitess,applift/vitess,dumbunny/vitess,enisoc/vitess,sougou/vitess,applift/vitess,rnavarro/vitess,rnavarro/vitess,enisoc/vitess,AndyDiamondstein/vitess,HubSpot/vitess,dumbunny/vitess,mattharden/vitess,tirsen/vitess,mahak/vitess,pivanof/vitess,aaijazi/vitess,davygeek/vitess,davygeek/vitess,applift/vitess,tinyspeck/vitess,sougou/vitess,sougou/vitess,aaijazi/vitess,vitessio/vitess,erzel/vitess,tinyspeck/vitess,applift/vitess,tirsen/vitess,vitessio/vitess,mapbased/vitess,mahak/vitess,mapbased/vitess,davygeek/vitess,AndyDiamondstein/vitess