Add 32-bit ARMv8 bots

Our 32-bit "arm" builds can run just fine on most ARMv8 devices.  This
mode of operation is called "aarch32", as opposed to the usual mode
we're used to thinking about of running 64-bit "arm64" binaries,
"aarch64".

(Unimportant side note: there are ARMv8 chips that support only
aarch64... I think e.g. the iPhone X's CPU?  There are also ARMv8 chips
that support only aarch32, rare and usually for tiny embedded things
like a watch.  All the devices we test with support both aarch64 and
aarch32.)

(Technically what we call "arm" is more properly "T32" for Thumb2 32,
and "arm64" is "A64" for... ARM 64.  This note is even less important
than the previous one.)

Android ships 64-bit Skia on devices that support it, but Chrome still
clings to 32-bit.  So I thought it'd make sense for us to run some of
these Chrome-like builds too.  I wasn't sure which ones, so I just went
nuts and mirrored all the Nexus5x bots.  If you notice bots that seem
under your purview and you really don't care about how Chrome would work
in that mode, please mark them in the code review and I'll drop them.

Change-Id: I3e67070c669f5c459f4c0f5f46a68529a8eb9afc
Reviewed-on: https://skia-review.googlesource.com/101545
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed