As shown in the commit description of https://crrev.com/c/1619763, the JSON
format was supposed to refer to a list of "spaces" and not "pages", this was a
typo.

Bug: v8:9186
Change-Id: I1a674dac8af4b27b7ee46041e8c7a533bad8e68b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1657917Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#62139}