Fix panics on schema changes

[max-hoffman]

fixes: #8504

Use schema hash to detect when database statistics might be incompatible. Drops all statistics for schema update. This could be improved to a subset of statistics if we wanted in the future.

[coffeegoddd]

@max-hoffman DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
f049f9a	ok	5937457

version	total_tests
f049f9a	5937457

correctness_percentage
100.0

[coffeegoddd]

@max-hoffman DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
b433c92	ok	5937457

version	total_tests
b433c92	5937457

correctness_percentage
100.0

[coffeegoddd]

@max-hoffman DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
3e50120	ok	5937457

version	total_tests
3e50120	5937457

correctness_percentage
100.0

[coffeegoddd]

@max-hoffman DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
a8c42da	ok	5937457

version	total_tests
a8c42da	5937457

correctness_percentage
100.0

[coffeegoddd]

@max-hoffman DOLT

comparing_percentages
100.000000 to 100.000000

version	result	total
bd30b7c	ok	5937457

version	total_tests
bd30b7c	5937457

correctness_percentage
100.0