tests: add sparserevlog requirement to test-sqlitestore.t
Looks like this test was missed when enabling sparse revlogs by default.
Differential Revision: https://phab.mercurial-scm.org/D5402
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.