BigQuery: request object not populated correctly for array query parameters

[tswast]

I recently documented how to use query parameters in BigQuery
https://cloud.google.com/bigquery/querying-data#bigquery-query-params-arrays-api

I found a problem with how the query parameters are supported in the client library. It does not set the type to ARRAY.

Also arrayType and arrayValues need to be in objects themselves. This is because arrays can also contain STRUCTs (but not other ARRAYs). Handing structs in arrays should maybe be a separate issue, though.

I was able to fix this for scalar types in tswast@909cf52 but tests need to be updated, plus we should have integration tests.