The --trace-gc-verbose flag was mistakenly reporting the generic LO space size
in place of the *code* LO space size.

Change-Id: Iddb83b540b0e0a201aa358649d91ef606721e0be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1554693
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60665}