Limit number of in-memory db connections to 1 per pool

We should always keep pool size of 1 for in-memory databases since every
:memory: db is separate from another.

Test: com.android.providers.contacts.util.UserUtilsTest
Bug: 64039907
Change-Id: If85af3eacfb5625036e29d44f88c1bebb338f46b
1 file changed