pgsql: Have the REPACK decoding worker use timeout values from the stee

Have the REPACK decoding worker use timeout values from the steering backend

The worker connects as the table owner in a new session, so a role- or
database-level lock_timeout and transaction_timeout unhelpfully apply to
it, possibly canceling the wait for older transactions. This cannot be
overridden by the REPACK calling session. Fix by passing the timeout
values from the steering backend via the DecodingWorkerShared struct and
adopting these values in the worker; this way, values from session-local
SET reach the worker too.

In passing, remove a pointless member from the same struct.

Author: Shihao Zhong <zhong950419(at)gmail(dot)com>
Backpatch-through: 19
Discussion: https://postgr.es/m/CAGRkXqTYaBjFvjtjPb1+=sZWvt93=2c472bmM+xdG7w9ZvAydA@mail.gmail.com

Branch
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REL_19_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/746a507a391b7c1d333ff969ab08d60575da9630

Modified Files
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src/backend/commands/repack.c | 5 ++++-
src/backend/commands/repack_worker.c | 11 ++++++++++-
src/include/commands/repack_internal.h | 5 ++++-
3 files changed, 18 insertions(+), 3 deletions(-)