Fix #2685: prevent CSE optimizer from causing short-circuiting issues, and add disable_optimizers setting

[Mytherin]

Fixes #2685

This PR exposes the disable_optimizers settings in SQL which allows optimizers to be disabled on a per-optimizer basis. This is useful for debugging to quickly figure out which optimizer causes issues.

Syntax:

SET disabled_optimizers TO 'expression_rewriter,filter_pushdown,join_order'

Available optimizers:

expression_rewriter
filter_pullup
filter_pushdown
regex_range
in_clause
join_order
deliminator
unused_columns
statistics_propagation
common_subexpressions
common_aggregate
column_lifetime
top_n
reorder_filter