Merged PRs

dolt

8522: libraries/doltcore/remotestorage: Improve connection reuse when fetching chunks from remote storage.
Improves performance of fetches from DoltHub, sql-server, and doltlab.
Improves some situations where routers and network access points do not respond well to clients which open a great number of connections to the same TCP endpoint, many of which live for a very short period of time.
http.DefaultClient comes with a default MaxIdleConnsPerHost of 2. Fetching with a high number of concurrent downloads results in many connections not being reused efficiently because they cannot get back into the idle pool because it is so small. Here we increase the MaxIdleConnsPerHost to be large enough so that our active connections during a fetch will fit within it.
Note: S3 limits a single HTTP connection to 100 requests, after which it is closed server-side. So currently dolt can still require a large number of new connections over the course of a pull, and the rate at which they are opened will depend on a number of factors including available throughput, round trip time resolving storage locations, etc. But this change will always be a big improvement over the old behavior.

2729: move applyEventScheduler logic and eventscheduler to builder
2727: fix dropped error in createView
2719: move applyUpdateAccumulators
This PR deletes the plan.RowUpdateAccumulator node, and directly injects an accumulatorIter into the rowexec tree in finalizeIters.
Doltgres fix: dolthub/doltgresql#909

Read Tests	MySQL	Dolt	Multiple
covering_index_scan	2.07	0.62	0.3
groupby_scan	13.7	16.71	1.2
index_join	1.39	2.35	1.7
index_join_scan	1.27	1.89	1.5
index_scan	34.33	54.83	1.6
oltp_point_select	0.18	0.27	1.5
oltp_read_only	3.49	5.47	1.6
select_random_points	0.34	0.67	2.0
select_random_ranges	0.39	0.64	1.6
table_scan	34.33	54.83	1.6
types_table_scan	75.82	144.97	1.9
reads_mean_multiplier			1.5

Write Tests	MySQL	Dolt	Multiple
oltp_delete_insert	8.13	5.88	0.7
oltp_insert	3.82	2.91	0.8
oltp_read_write	8.58	11.45	1.3
oltp_update_index	3.82	2.97	0.8
oltp_update_non_index	3.89	2.91	0.7
oltp_write_only	5.37	5.99	1.1
types_delete_insert	7.7	6.32	0.8
writes_mean_multiplier			0.9

TPC-C TPS Tests	MySQL	Dolt	Multiple
tpcc-scale-factor-1	99.4	40.78	2.4
tpcc_tps_multiplier			2.4

Overall Mean Multiple	1.60