desensitize Oracle to FLOAT/DOUBLE/DOUBLE_PRECISION differences
desensitize Oracle to FLOAT/DOUBLE/DOUBLE_PRECISION differences

Oracle Float will come back as DOUBLE_PRECISION
as a result of https://github.com/sqlalchemy/sqlalchemy/issues/5465.
Add some synonyms to prevent changes between these names from resulting
in autogenerate positives.

Change-Id: I6cdda7ff660ecf92884c18c663aef1c143a58da7

sqlalchemy/alembic,zzzeek/alembic