updated test meta table to provide explicit assembly mappings
updated test meta table to provide explicit assembly mappings

mjg17/ensembl,muffato/ensembl,at7/ensembl,Ensembl/ensembl,willmclaren/ensembl,at7/ensembl,james-monkeyshines/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,willmclaren/ensembl,james-monkeyshines/ensembl,muffato/ensembl,muffato/ensembl,danstaines/ensembl,danstaines/ensembl,mjg17/ensembl,at7/ensembl,james-monkeyshines/ensembl,muffato/ensembl,Ensembl/ensembl,Ensembl/ensembl,at7/ensembl,Ensembl/ensembl,mjg17/ensembl,danstaines/ensembl