Add support to resolve values of jsonb_object (and similar) functions

[cbruno10]

For the aws_pricing_product table, sometimes we want to get prices for specific resources based on ID, name, etc., so we try to run a query like:

with volume_list as (
  select
    region,
    volume_type
  from
    aws_ebs_volume
)
select
  p.price_per_unit,
  p.filters
from
  volume_list as v
  left join aws_pricing_product as p on
    p.service_code = 'AmazonEC2'
    and p.filters =  jsonb_object(ARRAY['regionCode', v.region]::TEXT[])::text ::jsonb 
    and p.attributes ->> 'volumeApiName' = v.volume_type

The query runs and doesn't seem to ever finish.

The query plan looks a bit strange:

> explain with volume_list as (
  select
    region,
    volume_type
  from
    aws_ebs_volume
)
select
  p.price_per_unit,
  p.filters
from
  volume_list as v
  left join aws_pricing_product as p on
    p.service_code = 'AmazonEC2'
    and p.filters =  jsonb_object(ARRAY['regionCode', v.region]::TEXT[])::text ::jsonb 
    and p.attributes ->> 'volumeApiName' = v.volume_type
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| QUERY PLAN                                                                                                                                                            |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Nested Loop Left Join  (cost=0.00..20000400010000.00 rows=25000000 width=64)                                                                                          |
|   ->  Foreign Scan on aws_ebs_volume  (cost=0.00..20000000000000.00 rows=1000000 width=200)                                                                           |
|   ->  Foreign Scan on aws_pricing_product p  (cost=0.00..400.00 rows=1 width=400)                                                                                     |
|         Filter: ((service_code = 'AmazonEC2'::text) AND (service_code = 'AmazonEC2'::text) AND ((attributes ->> 'volumeApiName'::text) = aws_ebs_volume.volume_type)) |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+