clang/mac/arm: make runnable on arm

We won't need this on the bots soon, but it's useful for running
the script locally to collect data like

- Use a newer cmake that has a universal binary
- Don't run all tests on arm since not all of them pass yet
- Minor adjustments to some conditionals

At some point, we'll have to explicitly set the default triple,
since at the moment the cross-built arm clang has a default intel
triple, but the arm-built arm clang has a default arm triple.
(Chromium's build passes an explicit triple, so it doesn't affect
chromium's build.)

No behavior change when running the script on an intel machine.

Bug: 1103322
Change-Id: I5683bf83abec5ba46bb197b8570196cd0027e857
Reviewed-by: Hans Wennborg <>
Commit-Queue: Nico Weber <>
Auto-Submit: Nico Weber <>
Cr-Commit-Position: refs/heads/master@{#871328}
GitOrigin-RevId: 45b4c709db4596ef108860adf00eb31a9f65d178
2 files changed