It will now return true for 32-bit constants as well.

When enabling this, two errors popped up: one in dissassembler where
we might have null hosts, and one in remembered set where we should be
compressing the address before storing.

As a drive-by: make ppc use full objects until their pointer compression
implementation is fully done.

Bug: v8:7703
Change-Id: I70f05f952d4e1305fe1fe030755f01f74ea5e5dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2187622Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67711}