Include full table scan in index statistics

[jycor]

Have StatsController also create an "empty" statistic entry to indicate no index for costing.

[coffeegoddd]

@jycor DOLT

read_tests	from_latency	to_latency	percent_change
covering_index_scan	2.35	2.3	-2.13
groupby_scan	68.05	62.19	-8.61
index_join	1.93	1.93	0.0
index_join_scan	1.32	1.32	0.0
index_scan	200.47	207.82	3.67
oltp_point_select	0.25	0.25	0.0
oltp_read_only	5.0	5.0	0.0
select_random_points	0.53	0.51	-3.77
select_random_ranges	0.67	0.64	-4.48
table_scan	200.47	207.82	3.67
types_table_scan	458.96	467.3	1.82

write_tests	from_latency	to_latency	percent_change
oltp_delete_insert	6.09	6.09	0.0
oltp_insert	3.13	3.13	0.0
oltp_read_write	11.24	11.24	0.0
oltp_update_index	3.3	3.3	0.0
oltp_update_non_index	3.02	2.97	-1.66
oltp_write_only	6.21	6.21	0.0
types_delete_insert	6.91	6.79	-1.74

[coffeegoddd]

@jycor DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
f9d23ac	ok	5937471

version	total_tests
f9d23ac	5937471

correctness_percentage
100.0

[coffeegoddd]

@jycor DOLT

test_name	from_latency_p95	to_latency_p95	percent_change
tpcc-scale-factor-1	45.79	45.79	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	677e2f7	53.03	dolt	7687d87	53.12	0.17

[coffeegoddd]

@jycor DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
5f3c804	ok	5937471

version	total_tests
5f3c804	5937471

correctness_percentage
100.0

[coffeegoddd]

@jycor DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
ecec31a	ok	5937471

version	total_tests
ecec31a	5937471

correctness_percentage
100.0

[coffeegoddd]

@jycor DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
7687d87	ok	5937471

version	total_tests
7687d87	5937471

correctness_percentage
100.0