The stub cache doubles in size when switching to 64-bit. The references
stored in it are not currently compressed even with ptr-compr enabled.

This patch compresses those references so the table is the same size on
32- and 64-bit architectures, which is beneficial on benchmarks which
utilise the stub cache heavily.

Reducing the stub cache size has lead to an improvement of 0.7% in
runs/minute being observed on Speedometer on a Pixel device, and 0.4% on
a Pixel3 device.

Also add constructors to [Strong]TaggedValue to support compression.

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_arm64_pointer_compression_rel_ng
Change-Id: I3b643d674356deaa129588189df7adfc91d15db4
Bug: v8:7703
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1635694
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62308}