This reverts commit f9a2e24b.

Reason for revert: gc stress failures not all fixed by follow up.

Original change's description:
> [cleanup] Refactor the Factory
> 
> There is no good reason to have the meat of most objects' initialization
> logic in heap.cc, all wrapped by the CALL_HEAP_FUNCTION macro. Instead,
> this CL changes the protocol between Heap and Factory to be AllocateRaw,
> and all object initialization work after (possibly retried) successful
> raw allocation happens in the Factory.
> 
> This saves about 20KB of binary size on x64.
> 
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Icbfdc4266d7be8b48d2fe085f03411743dc6a0ca
> Reviewed-on: https://chromium-review.googlesource.com/959533
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52416}

TBR=jkummerow@chromium.org,yangguo@chromium.org,mstarzinger@chromium.org,hpayer@chromium.org

Change-Id: Idbbc53478742f3e9525eee83342afc6aedae122f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/999414Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52420}