Use buffer in `prollyJoiner`

[jycor]

[jycor]

#benchmark

[github-actions[bot]]

@jycor workflow run: https://github.com/dolthub/dolt/actions/runs/19116422192

[coffeegoddd]

@jycor DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
1701ee6	ok	5937471

version	total_tests
1701ee6	5937471

correctness_percentage
100.0

[coffeegoddd]

@jycor DOLT

test_name	from_latency_p95	to_latency_p95	percent_change
tpcc-scale-factor-1	65.65	65.65	0.0

test_name	from_server_name	from_server_version	from_tps	to_server_name	to_server_version	to_tps	percent_change
tpcc-scale-factor-1	dolt	bd84680be20499e5bea482c616927a34be6d4d74	35.81	dolt	1701ee6f83f489e6cf4ed5660a0361d29c33d6a6	36.17	1.01

[coffeegoddd]

@jycor DOLT

read_tests	from_latency	to_latency	percent_change
covering_index_scan	0.68	0.68	0.0
groupby_scan	17.01	16.71	-1.76
index_join	2.35	2.35	0.0
index_join_scan	1.39	1.39	0.0
index_scan	28.67	28.67	0.0
oltp_point_select	0.3	0.3	0.0
oltp_read_only	5.28	5.28	0.0
select_random_points	0.62	0.62	0.0
select_random_ranges	0.64	0.64	0.0
table_scan	28.16	28.16	0.0
types_table_scan	99.33	99.33	0.0

write_tests	from_latency	to_latency	percent_change
oltp_delete_insert	6.67	6.67	0.0
oltp_insert	3.25	3.25	0.0
oltp_read_write	11.87	11.87	0.0
oltp_update_index	3.36	3.3	-1.79
oltp_update_non_index	3.25	3.25	0.0
oltp_write_only	6.43	6.43	0.0
types_delete_insert	7.04	7.04	0.0