Fix SQLiteDatabaseTest#testCloseIdleConnection

Bug: 287127336

The test verifies that connection #0 is not active, but an earlier
test leaves an open database with an active connection #0.  This CL
changes the earlier test to clean up after itself.

Test: atest
 * CtsDatabaseTestCases
Change-Id: I9fcfa7146fb8b05df1ad694bccae7059d7408b31
1 file changed