pgsql: Use an LWLock instead of a spinlock in waitlsn.c

Use an LWLock instead of a spinlock in waitlsn.c

This should prevent busy-waiting when number of waiting processes is high.

Discussion: https://postgr.es/m/202404030658.hhj3vfxeyhft%40alvherre.pgsql
Author: Alvaro Herrera

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/25f42429e2ff2acca35c9154fc2e36b75c79227a

Modified Files
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src/backend/commands/waitlsn.c                  | 15 +++++++--------
src/backend/utils/activity/wait_event_names.txt |  1 +
src/include/commands/waitlsn.h                  |  5 +----
src/include/storage/lwlocklist.h                |  1 +
4 files changed, 10 insertions(+), 12 deletions(-)