Skip DEBUG_VERBOSE end print for point writes

Point writes are recorded with the 2-argument
interleaved_insert::Result constructor, which leaves endRemaining
indeterminate, so the Phase 2 debug print in interleavedWrites read an
indeterminate span and, with stack garbage left over from an earlier
call, dereferenced a freed pointer. Confirmed with valgrind on a point
write following a range write: "Conditional jump or move depends on
uninitialised value(s)" and "Invalid read of size 1" at
ConflictSet.cpp:4984, and ASan heap-use-after-free in the same place.

Only print the end search path and spans for range writes, mirroring the
`if (e != nullptr)` check that already guards the endInsertionPoint
forwarding-chain fixup a few lines above. Production code already treats
endRemaining as range-write only, so nothing else changes.

ConflictSet.cpp

@@ -3904,12 +3904,11 @@ struct Result {
   Result() = default;
   Result(Node *insertionPoint, TrivialSpan remaining)
       : insertionPoint(insertionPoint), remaining(remaining),
-        endInsertionPoint(nullptr), endRemaining{}, nextRangeWrite(nullptr) {}
+        endInsertionPoint(nullptr) {}
   Result(Node *insertionPoint, TrivialSpan remaining, Node *endInsertionPoint,
          TrivialSpan endRemaining)
       : insertionPoint(insertionPoint), remaining(remaining),
-        endInsertionPoint(endInsertionPoint), endRemaining(endRemaining),
-        nextRangeWrite(nullptr) {}
+        endInsertionPoint(endInsertionPoint), endRemaining(endRemaining) {}
 
   Node *insertionPoint;
   TrivialSpan remaining;