alternator-test: some more GSI tests
alternator-test: some more GSI tests

Expand the GSI test suite. The most important new test is
test_gsi_key_not_in_index(), where the index's key includes just one of
the base table's key columns, but not a second one. In this case, the
Scylla implementation will nevertheless need to add the second key column
to the view (as a clustering key), even though it isn't considered a key
column by the DynamoDB API.

Signed-off-by: Nadav Har'El <625169824b719df98706d88646d0aae6f368ae4d@scylladb.com>
Message-Id: <20190718085606.7763-1-625169824b719df98706d88646d0aae6f368ae4d@scylladb.com>

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla