rts: Fix SET_HDR initialization of retainer set
This fixes a regression in retainer set profiling introduced by
b0293f78. Prior to that commit
the heap traversal word would be initialized by SET_HDR
using
LDV_RECORD_CREATE
. However, the commit added a doingLDVProfiling
check in LDV_RECORD_CREATE
, meaning that this initialization no longer
happened.
Given that this initialization was awkwardly indirectly anyways, I have
fixed this by explicitly initializating the heap traversal word to
NULL
in SET_PROF_HDR
. This is equivalent to the previous behavior,
but much more direct.
Fixes #24513 (closed).