[infra] Shuffle Mac CPU and xSAN jobs to MacBookPro11.5.

I'm keeping the Release jobs for a few commits for blame.

There are a few reasons for this change:
 - This will free up more Mac VMs for Build jobs.
 - The CPU jobs currently run on VMs, which don't provide reliable perf
   numbers.
 - The two bare-metal MacMini7.1 bots (currently running the GPU TSAN
   jobs) are over-capacity.
 - Lets us test AVX2 rather than AVX.

I used the MacBookPro11.5 for all of these, but we could spread them
out to other Mac bots if it's too much load for these bots.

No-Try: true
Change-Id: I8c97e194c4f3e0018e7e646b93c3d96db8d0ca82
Reviewed-on: https://skia-review.googlesource.com/145431
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
3 files changed