- move a few memusage tests out of "backend".  something is up w/ cx_Oracle when the suite runs, such as a background thread or something like that, which is affecting these tests a bit.
- move a few memusage tests out of "backend".  something is up w/ cx_Oracle
when the suite runs, such as a background thread or something like that,
which is affecting these tests a bit.

Change-Id: I52d50a44778ec1eecb8e335ae59b1a4773e80a79

monetate/sqlalchemy,graingert/sqlalchemy,j5int/sqlalchemy,graingert/sqlalchemy,zzzeek/sqlalchemy,monetate/sqlalchemy,j5int/sqlalchemy,sqlalchemy/sqlalchemy,wujuguang/sqlalchemy,wujuguang/sqlalchemy