pgsql: Preserve tz when converting to jsonb timestamptz

Preserve tz when converting to jsonb timestamptz

This removes an inconsistency in the treatment of different datatypes by
the jsonpath timestamp_tz() function. Conversions from data types that
are not timestamp-aware, such as date and timestamp, are now treated
consistently with conversion from those that are such as timestamptz.

Author: David Wheeler
Reviewed-by: Junwang Zhao and Jeevan Chalke

Discussion: https://postgr.es/m/7DE080CE-6D8C-4794-9BD1-7D9699172FAB%40justatheory.com

Backpatch to release 17.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/524d490a9f4ab81d86bbedc6e429fbc27776351c

Modified Files
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src/backend/utils/adt/jsonpath_exec.c | 25 +++++++++++++++++++++++++
src/test/regress/expected/jsonb_jsonpath.out | 4 ++--
2 files changed, 27 insertions(+), 2 deletions(-)