Fix two issues with recently-introduced nbtree test

Michael Paquier <michael@paquier.xyz>

Commit: 06817fc8a4b739cc2d1aa87071d9e20d483fd678
Author: Michael Paquier <michael@paquier.xyz>
Date: 2025-12-10T02:56:42Z
Fix two issues with recently-introduced nbtree test

REGRESS has forgotten about the test nbtree_half_dead_pages, and a
.gitignore was missing from the module.

Oversights in c085aab27819 for REGRESS and 1e4e5783e7d7 for the missing
.gitignore.

Discussion: https://postgr.es/m/aTipJA1Y1zVSmH3H@paquier.xyz

Files

Discussion

Cited messages not in the archive: aTipJA1Y1zVSmH3H@paquier.xyz