perf: use LATERAL instead of CTE for json body

* add pgbench test for INSERT and RPC
* use LATERAL for RPC and INSERT
* add tests for inlining

test/pgbench/1652/new.sql

@@ -0,0 +1,20 @@
+WITH pgrst_source AS (
+  SELECT pgrst_call.*
+  FROM (
+    SELECT '{"id": 4}'::json as json_data
+  ) pgrst_payload,
+  LATERAL (
+    SELECT CASE WHEN json_typeof(pgrst_payload.json_data) = 'array' THEN pgrst_payload.json_data ELSE json_build_array(pgrst_payload.json_data) END AS val
+  ) pgrst_uniform_json,
+  LATERAL (
+    SELECT * FROM json_to_recordset(pgrst_uniform_json.val) AS _("id" integer) LIMIT 1
+  ) pgrst_body,
+  LATERAL "test"."get_projects_below"("id" := pgrst_body.id) pgrst_call
+)
+SELECT
+  null::bigint AS total_result_set,
+  pg_catalog.count(_postgrest_t) AS page_total,
+  coalesce(json_agg(_postgrest_t), '[]')::character varying AS body,
+  nullif(current_setting('response.headers', true), '') AS response_headers,
+  nullif(current_setting('response.status', true), '') AS response_status
+FROM (SELECT "projects".* FROM "pgrst_source" AS "projects") _postgrest_t;