Merge cockroachdb#150793

150793: sql/jsonpath: index accelerate jsonb_path_exists filters r=ZhouXing19 a=ZhouXing19

Fixes: cockroachdb#154044

This commit is to generate inverted expression for filter (i.e. WHERE
clauses) with the `jsonb_path_exists` function.

Release note (sql change): We now support index acceleration for a subset of jsonb_path_exists filters.

Given the `jsonb_path_exists(json_obj, json_path_expression)`, we only support
inverted index for json_path_expression that matches one of the following
patterns:

- The json_path_expression must NOT be in STRICT mode.
- keychain mode: `$.[key|wildcard].[key|wildcard]...`
	- For this mode, we will generate a prefix span for the inverted expression.
- filter with end value mode, with equality check: `$.[key|wildcard]? (`@.[key|wildcard].[key|wildcard]...` == [string|number|null|boolean])`
    - For this mode, since the end value is fixed, we will generate a single value span.

Specifically, we don't support the following edge case:

- `$`
- `$[*]`
- `$.a.b.c == 12` or `$.a.b.c > 12` or `$.a.b.c < 12` (operation expression)
- `$.a.b ? (`@.a` > 10)` (filter, with inequality check)

Note that the cases we support is to use `jsonb_path_exists` in filters,
as in, when they are used in the WHERE clause.

Co-authored-by: ZhouXing19 <[email protected]>

Author: craig[bot]