Add a 64-bit ARM builder to the CQ.
Add a 64-bit ARM builder to the CQ.

It's possible this rarely breaks, but I do write ARMv8 code frequently
enough that it'll help prevent broken trees.

BUG=skia:

Review URL: https://codereview.chromium.org/1209763003

qrealka/skia-hc,HalCanary/skia-hc,rubenvb/skia,shahrzadmn/skia,ominux/skia,todotodoo/skia,qrealka/skia-hc,nvoron23/skia,HalCanary/skia-hc,nvoron23/skia,ominux/skia,todotodoo/skia,pcwalton/skia,tmpvar/skia.cc,noselhq/skia,ominux/skia,nvoron23/skia,tmpvar/skia.cc,Hikari-no-Tenshi/android_external_skia,nvoron23/skia,Jichao/skia,google/skia,shahrzadmn/skia,pcwalton/skia,shahrzadmn/skia,aosp-mirror/platform_external_skia,ominux/skia,todotodoo/skia,nvoron23/skia,qrealka/skia-hc,qrealka/skia-hc,aosp-mirror/platform_external_skia,Jichao/skia,shahrzadmn/skia,shahrzadmn/skia,ominux/skia,google/skia,Jichao/skia,Jichao/skia,HalCanary/skia-hc,HalCanary/skia-hc,vanish87/skia,vanish87/skia,rubenvb/skia,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,vanish87/skia,Jichao/skia,Hikari-no-Tenshi/android_external_skia,ominux/skia,rubenvb/skia,rubenvb/skia,google/skia,pcwalton/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,pcwalton/skia,pcwalton/skia,shahrzadmn/skia,vanish87/skia,google/skia,nvoron23/skia,noselhq/skia,rubenvb/skia,nvoron23/skia,vanish87/skia,vanish87/skia,ominux/skia,HalCanary/skia-hc,pcwalton/skia,qrealka/skia-hc,todotodoo/skia,aosp-mirror/platform_external_skia,todotodoo/skia,Hikari-no-Tenshi/android_external_skia,noselhq/skia,tmpvar/skia.cc,vanish87/skia,todotodoo/skia,aosp-mirror/platform_external_skia,vanish87/skia,qrealka/skia-hc,nvoron23/skia,pcwalton/skia,HalCanary/skia-hc,HalCanary/skia-hc,shahrzadmn/skia,todotodoo/skia,Jichao/skia,tmpvar/skia.cc,shahrzadmn/skia,HalCanary/skia-hc,shahrzadmn/skia,google/skia,noselhq/skia,aosp-mirror/platform_external_skia,tmpvar/skia.cc,google/skia,Jichao/skia,rubenvb/skia,todotodoo/skia,noselhq/skia,vanish87/skia,Jichao/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,tmpvar/skia.cc,noselhq/skia,google/skia,google/skia,pcwalton/skia,aosp-mirror/platform_external_skia,ominux/skia,pcwalton/skia,aosp-mirror/platform_external_skia,todotodoo/skia,Jichao/skia,aosp-mirror/platform_external_skia,rubenvb/skia,google/skia,tmpvar/skia.cc,aosp-mirror/platform_external_skia,noselhq/skia,rubenvb/skia,nvoron23/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,tmpvar/skia.cc,qrealka/skia-hc,google/skia,ominux/skia,tmpvar/skia.cc,rubenvb/skia,rubenvb/skia,noselhq/skia,noselhq/skia,Hikari-no-Tenshi/android_external_skia