Changes

use No_scan_tag and NOT_MARKABLE to indicate free block
 (commit: 4b7b06d)

change shared pools heap representation to indicate contiguous free ranges
update sweep and shared heap allocation to use this
 (commit: c1a457f)

add prefetching
 (commit: 634f0fa)

add Changes
 (commit: d443e61)

actually prefetch a page ahead
 (commit: 85436a9)

restore split asserts
 (commit: 066cf23)

clarify comment in verify_pool
 (commit: 395cc33)

fix bug in compaction
 (commit: 868adce)

write Debug_free_major in to newly initialised pools
 (commit: 32fec02)

fix bug in pool_finalise
 (commit: aa2a6e9)

simplify macro
 (commit: 6f4c921)

Update runtime/shared_heap.c

Co-authored-by: Damien Doligez <damien.doligez@gmail.com>
 (commit: 40ac897)

Update runtime/shared_heap.c

Co-authored-by: Damien Doligez <damien.doligez@gmail.com>
 (commit: 4f6ad7a)

restore atomic header read
 (commit: 0beada7)

make note about GC pacing logic
 (commit: a968da8)

Update runtime/shared_heap.c

Co-authored-by: Damien Doligez <damien.doligez@gmail.com>
 (commit: 7ee99a6)

wh -> Whsize_hd
 (commit: 0de6b32)

always update the pointer in the last free block
 (commit: 8954ebc)

revert all_used annotation
 (commit: 9ee312a)

use POOL_FIRST_BLOCK
 (commit: 29be988)