Remove `MigrationTest#test_create_table_with_custom_sequence_name`
Remove `MigrationTest#test_create_table_with_custom_sequence_name`

This test is only executed for OracleAdapter.

https://github.com/rsim/oracle-enhanced/pull/1846 adds
an equivalent spec for Oracle enhanced adapter.

Edouard-chin/rails,jeremy/rails,mechanicles/rails,Stellenticket/rails,notapatch/rails,yhirano55/rails,mechanicles/rails,yalab/rails,rails/rails,tjschuck/rails,rails/rails,arunagw/rails,rafaelfranca/omg-rails,joonyou/rails,schuetzm/rails,fabianoleittes/rails,Envek/rails,gauravtiwari/rails,vipulnsward/rails,georgeclaghorn/rails,georgeclaghorn/rails,vipulnsward/rails,BlakeWilliams/rails,prathamesh-sonpatki/rails,Envek/rails,fabianoleittes/rails,shioyama/rails,tjschuck/rails,Stellenticket/rails,lcreid/rails,esparta/rails,jeremy/rails,schuetzm/rails,Erol/rails,Stellenticket/rails,Envek/rails,Stellenticket/rails,betesh/rails,eileencodes/rails,Erol/rails,iainbeeston/rails,shioyama/rails,prathamesh-sonpatki/rails,schuetzm/rails,esparta/rails,esparta/rails,MSP-Greg/rails,Envek/rails,notapatch/rails,flanger001/rails,georgeclaghorn/rails,BlakeWilliams/rails,eileencodes/rails,prathamesh-sonpatki/rails,starknx/rails,vipulnsward/rails,kddeisz/rails,MSP-Greg/rails,esparta/rails,rails/rails,yhirano55/rails,bogdanvlviv/rails,tgxworld/rails,betesh/rails,Erol/rails,bogdanvlviv/rails,yawboakye/rails,lcreid/rails,lcreid/rails,jeremy/rails,jeremy/rails,tjschuck/rails,yhirano55/rails,kmcphillips/rails,yhirano55/rails,shioyama/rails,arunagw/rails,palkan/rails,flanger001/rails,kmcphillips/rails,joonyou/rails,kddeisz/rails,repinel/rails,iainbeeston/rails,fabianoleittes/rails,yalab/rails,kmcphillips/rails,kddeisz/rails,yalab/rails,notapatch/rails,repinel/rails,Vasfed/rails,iainbeeston/rails,iainbeeston/rails,palkan/rails,prathamesh-sonpatki/rails,tgxworld/rails,palkan/rails,bogdanvlviv/rails,starknx/rails,yawboakye/rails,tgxworld/rails,vipulnsward/rails,yahonda/rails,tjschuck/rails,palkan/rails,rails/rails,Edouard-chin/rails,yahonda/rails,schuetzm/rails,Edouard-chin/rails,flanger001/rails,MSP-Greg/rails,rafaelfranca/omg-rails,joonyou/rails,yalab/rails,EmmaB/rails-1,mechanicles/rails,flanger001/rails,fabianoleittes/rails,kmcphillips/rails,yawboakye/rails,notapatch/rails,starknx/rails,georgeclaghorn/rails,Vasfed/rails,betesh/rails,mechanicles/rails,yawboakye/rails,arunagw/rails,MSP-Greg/rails,lcreid/rails,Vasfed/rails,tgxworld/rails,BlakeWilliams/rails,yahonda/rails,rafaelfranca/omg-rails,Edouard-chin/rails,eileencodes/rails,repinel/rails,Vasfed/rails,joonyou/rails,eileencodes/rails,yahonda/rails,EmmaB/rails-1,EmmaB/rails-1,arunagw/rails,gauravtiwari/rails,gauravtiwari/rails,repinel/rails,kddeisz/rails,Erol/rails,betesh/rails,bogdanvlviv/rails,BlakeWilliams/rails,shioyama/rails