This reverts commit b1dd8287.

Reason for revert: Breaking fuschia build https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Fuchsia%20-%20builder/13592/overview

Original change's description:
> [builtins] Remap builtins on Linux
>
> This is a CL similar to
> https://chromium-review.googlesource.com/c/v8/v8/+/3553006, but on Linux
> rather than macOS. The goal is to allow builtins to use short builtin
> calls without paying a memory cost, by remapping rather than copying
> them.
>
> However, while macOS has a system call making this easier, on Linux we
> don't have one on most kernels. There is the recently-introduced
> mremap(MREMAP_DONTUNMMAP), which is available in 5.7, but only works on
> anonymous mappings until 5.13, which is too recent for most Android
> devices.
>
> Instead, we open() the file containing the builtins, and mmap() it at
> the desired location.
>
> Change-Id: I4524f349948b8f48c4536cf392a1cd179662a6cc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3570426
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Jakob Linke <jgruber@chromium.org>
> Commit-Queue: Benoit Lize <lizeb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80022}

Change-Id: I0093fe84216f8c8fd1a8691c53817e578d92fa40
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3594009
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Owners-Override: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80028}