This is a reland of cee2f772

Original change's description:
> [build] disable C++ optimization for mksnapshot code.
> 
> By disabling C++ optimizations for code that's only run in mksnapshot,
> that is, CSA and Torque-generated code, we can save compile time.
> I observed up to 2x improvements of compile time for some files,
> while the mksnapshot time did not increase significantly.
> 
> Bug: v8:7629
> Change-Id: I96be2966611b2471b68023e0dd9e351d94f0013c
> Reviewed-on: https://chromium-review.googlesource.com/c/1460941
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#59585}

Bug: v8:7629
Change-Id: I8330f93173ab3d7b400e15ea4935bbe8256b250f
Reviewed-on: https://chromium-review.googlesource.com/c/1473292
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59606}