Key field incorrect when only ROWKEY appears in projection

[big-andy-coates]

Given a C*AS statement that contains a projection where the key field of the source is not present AND ROWKEY is THEN the key field of the resultant source stored in the metastore is incorrect.

The net result of this is we miss an opportunity to avoid a repartition step on downstream queries that require the source to be (re-)keyed on the field.

e.g.

Given the SQL statement:

-- given 'input' with keyfield 'foo'...
CREATE STREAM INPUT (foo INT, bar INT) WITH (kafka_topic='input_topic', key='foo', value_format='JSON');

-- given 'output' where 'foo' not in projection but 'rowkey' is:
CREATE STREAM OUTPUT AS SELECT ROWKEY AS ID FROM INPUT;

Expected result: The keyField of OUTPUT should be set to ID as this field always matches the key of the output records

Actual result: the keyField of OUTPUT is set to null.

The same is true for joins.

[big-andy-coates]

Closing as we've removing WITH(KEY) anyway. #3537