Creates one database per sql test

A lot of sql tests are failing when running concurrently on the same
database. This patch drastically reduces the number of errors found
by creating one database for each test.

Related to blueprint sql-unit-tests-on-real-backend

Change-Id: I5a5f3a9f141c45a6c3c645e3b18089f442d29138
Merge "Creates one database per sql test"