Make clickhouse tuples work

[alrevuelta]

closes #2338

[alrevuelta]

note. this PR does not address tuple.-1 which seems to be valid clickhouse syntax.

Extracts an element from a tuple by index or name.

For access by index, an 1-based numeric index is expected. For access by name, the element name can be provided as a string (works only for named tuples).

Negative indexes are supported. In this case, the corresponding element is selected, numbered from the end. For example, tuple.-1 is the last element in the tuple.

An optional third argument specifies a default value which is returned instead of throwing an exception when the accessed element does not exist. All arguments must be constants.

This function has zero runtime cost and implements the operators x.index and x.name.

source: https://clickhouse.com/docs/sql-reference/functions/tuple-functions#tupleelement

[iffyio]

not sure I follow the patch/tests - are we saying that without this PR, a sql like t.1 tokenizes to something other than what's being asserted (if so what does the previous behavior tokenized to)?

[iffyio]

does this behavior differ from parse_compound_expr handling (if so how, on a first glance they look identical syntax wise)?