This reverts commit b5da9fcb.

Reason for revert: Breaks pointer compression bot:
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20-%20pointer%20compression/3098

Original change's description:
> [ptr-compr] New RelocInfo for compressed pointers.
> 
> New enum RelocInfo::COMPRESSED_EMBEDDED_OBJECT created to support
> compressed pointers in generated code. Enum name EMBEDDED_OBJECT
> changed to FULL_EMBEDDED_OBJECT.
> 
> RelocInfo::[set_]target_object() abstract away the difference between
> FULL_EMBEDDED_OBJECT and COMPRESSED_EMBEDDED_OBJECT.
> 
> Compressed embedded objects can only be created at this time on
> x64 with pointer compression turned on. Arm64 constant pools don't
> support compressed objects at this time.
> 
> Bug: v8:7703
> Change-Id: I03bfd84effa33c65cf9bcefa5df680ab7eace9dd
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1547661
> Commit-Queue: Michael Stanton <mvstanton@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61076}

TBR=ulan@chromium.org,mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,ishell@chromium.org

Change-Id: I262b2b98315fa987c5a66b1050dc726563ccdb2d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7703
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1588135Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61087}