Use marking already made several assumptions about node numbering
running just before it (in particular, that loop Phis can't be marked
when visited, but only when the loop back edge is visited). This wasn't
too bad initially, but now we have to bend over backwards to extract the
node id at loop headers for lifetime extension.

So, merge the numbering into the use marking.

Bug: v8:7700
Change-Id: I2f2e8feec8d0e25e302e92988109d88621879cd5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3797830Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82167}