The following offset getters in ThreadLocalAllocBuffer are unused and can be removed. They are left-overs from when we had FastTLABRefill support.

static ByteSize size_offset();
static ByteSize refill_waste_limit_offset();
static ByteSize number_of_refills_offset();
static ByteSize fast_refill_waste_offset();
static ByteSize slow_allocations_offset();