perf: Optimize regexp match and not match for .*foo.* cases

[petern48]

Which issue does this PR close?

• Closes Expr. simplification / rewrite: regex .*foo.* #20579

Rationale for this change

Improved query performance by optimizing logical plan

What changes are included in this PR?

Added optimization rules to perform the following logic

• s ~ '.*foo.*' -> contains(s, foo)
• s !~ '.*foo.*' -> not(contains(s, foo))
• s ~ '.*.*' -> is_not_null(s)
• s !~ '.*.*' -> false

Additionally, I found that the existing optimization for s !~ .* was incorrectly converting the condition to s = '', which would return True for rows where s was empty string (''). I confirmed this is different from default non-optimized query, which returns no rows even if some are empty string or NULL.

The reasoning behind it always returning False is that .* matches the empty string so not match should not include it. Additionally, NULL aren't returned either because NULL ! '.*results inNULL`, not True. Therefore this condition is always False.

Are these changes tested?

Added tests and updated existing tests to pass after fixing the bug in the pre-existing optimization.

Are there any user-facing changes?

This is a slight behavior change due to fixing a bug in the pre-existing optimization. Previously, s !~ '.*' would return rows where s was empty string. This PR fixes the bug so that no rows are returned, which matches the behavior when no optimizations are applied.