This reverts commit 10348e8e.

Reason for revert: https://crbug.com/1125951

Original change's description:
> [wasm][liftoff] Emit safepoints for externref values on the stack
> 
> With this CL we emit safepoint maps for externref values on the Liftoff
> value stack. With that there is support for externref parameters and
> locals in Liftoff, as well as for intermediate values of type
> externref.
> 
> R=​thibaudm@chromium.org
> 
> Bug: v8:7581
> Change-Id: I2df0a8d00b2da33fe06ff474b039cca4c7be726d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2387571
> Commit-Queue: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69725}

TBR=ahaas@chromium.org,thibaudm@chromium.org

Change-Id: I4cdf7fedfc91cd99302d5cb05e242dbb032c5803
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7581
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2398529Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69754}