This CL can be used as a base for specialising CompressedSigned and
CompressedPointer.

B

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng,v8_linux64_arm64_pointer_compression_rel_ng
Bug: v8:8977, v8:7703
Change-Id: I43c8e7f57021ac506822aba5bbd4bdf6cc3159ba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1543731
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60827}