Remove is_nacl from .gn and .gni files

Mostly written by gemini CLI, with this prompt:

> you're in a checkout of the chromium project. we recently removed
> support for native client, which means that is_nacl is always false in
> .gn files, and BUILDFLAG(IS_NACL) is always false in .cc files.
> can you clean up some of the instances?
> only look at BUILD.gn and .gni files, don't touch BUILDCONFIG.gn

It messed up testing/test.gni so I did that file manually. It also hung
in "Commencing Search Refinement" for over 7 minutes once, so I
interrupted it and told it to try again.

Otherwise, I just had to hit "enter" to confirm every now and then while
doing something else.

I told it to stop when it was done with .gn / .gni files and it wanted
to move on to .cc files.

I manually updated two comments.

Bug: 40511454
Change-Id: I268afe98a4721d34ad717ede1d34c6690233be1c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6723712
Auto-Submit: Nico Weber <[email protected]>
Reviewed-by: Hans Wennborg <[email protected]>
Reviewed-by: James Zern <[email protected]>
Reviewed-by: Stephen Nusko <[email protected]>
Commit-Queue: Nico Weber <[email protected]>
Reviewed-by: Tom Sepez <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1485296}
NOKEYCHECK=True
GitOrigin-RevId: c4531a4a2f348724000a814cfa40ef0bbf0831c7
1 file changed