Improve the working copy query tests a bit by adding a special list of
statements that just do a single read from the start of a table, as
Sqlite reports these differently between 3.7.X and 3.8.x.

Also tell our analyzer that the lock table needs two column index
usage to be effective.

This fixes a false positive test failure for Sqlite 3.8.X.

* subversion/tests/libsvn_wc/wc-queries-test.c
  (slow_statements): Add STMT_UPDATE_LOCK_REPOS_ID as slow, which was
    previously undetected.
    Move STMT_LOOK_FOR_WORK to the new...
  (primary_key_statements): list. Add the almost identical
    STMT_SELECT_WORK_ITEM.
  (is_node_table): Handle the repository 'lock' table as two key table.
  (test_query_expectations): Use primary_key_statements to fix the
    expectations for both Sqlite 3.8.X and 3.7.X.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1542774 13f79535-47bb-0310-9956-ffa450edef68