This reverts commit a7c7e8f6.

Reason for revert: TSAN failures.

Original change's description:
> [heap] Handle bytecode arrays in concurrent marker.
> 
> Bytecode array visitor has a side-effect of incrementing the age counter.
> 
> This patch makes the increment atomic and thus safe for the concurrent
> marker.
> 
> Bug: chromium:694255
> Change-Id: I36c65b02ace8d366206bd8295e72aaa19742ed56
> Reviewed-on: https://chromium-review.googlesource.com/610001
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#47317}

TBR=ulan@chromium.org,rmcilroy@chromium.org

Change-Id: Iceff1e5925bb6ad7c03f858aa2f1fa62240f6909
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:694255
Reviewed-on: https://chromium-review.googlesource.com/612069Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47319}