The InnerPointerToCodeCache was masking out the Page address to get stable
hashes. However, for pointers into the embedded code this still introduces a
sources of randomness due to how the data is mapped in. This is fixed by
using offsets relative to the start of the embedded data.

Hopefully this will fix one category of flaky tests unde with
v8_enable_verify_predictable  enabled.

Change-Id: I6bc3a1b6a03555341a9e4387e8bc058921298ef1
Reviewed-on: https://chromium-review.googlesource.com/c/1327045Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57392}