Add unlikely() to CHECK_FOR_INTERRUPTS()
Add the unlikely() branch hint macro to CHECK_FOR_INTERRUPTS().
Backpatch to REL_10_STABLE where we first started using unlikely().
Discussion: https://www.postgresql.org/message-id/flat/
8692553c-7fe8-17d9-cbc1-
7cddb758f4c6%40joeconway.com