Allow 32-bit mac->win cross builds (and as a side effect, arm64 cross builds).

After https://chromium-review.googlesource.com/c/v8/v8/+/1534635 this
works well enough automatically.

Additionally, this assert was unintentionally also hit with target_cpu =
"arm64", so this CL fixes that too.

Bug: 794838,893460
Change-Id: I32d7a67b2f818aacfaeef39a03a1107b596b9dfb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1536310
Auto-Submit: Nico Weber <[email protected]>
Reviewed-by: Adam Klein <[email protected]>
Commit-Queue: Nico Weber <[email protected]>
Cr-Commit-Position: refs/heads/master@{#644395}
2 files changed