[liftoff][cleanup] Rename DEBUG_CODE_COMMENT macro

The code used to be only enabled in debug mode. Now that we have a
separate v8_code_comments gn arg, this is not the case any more. Hence
remove the "DEBUG_" prefix from the macro.

R=ahaas@chromium.org

Change-Id: I60215e3b07d6cb0cee5076136834e4bb5a13355b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2982345Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75378}