Introduce new qc_parse() prototype

It is now possible to specify what information the caller is interested
in. With this the cost for collecting information during the query parsing
that nobody is interested in can be avoided.

query_classifier/test/crash_qc_sqlite.c

@@ -51,7 +51,7 @@ int main()
         // being of the opinion that the statement was not the one to be
         // classified and hence an alien parse-tree being passed to sqlite3's
         // code generator.
-        qc_parse(stmt);
+        qc_parse(stmt, QC_COLLECT_ALL);
 
         qc_process_end(QC_INIT_BOTH);