Use explicit alignment for 8-byte types
Use explicit alignment for 8-byte types

See:
https://software.intel.com/en-us/blogs/2011/08/18/understanding-x86-vs-arm-memory-alignment-on-android

alignof(uint64_t) is not consistent across x64 and x86, and so it's not
safe to use this.  This scenario can happen in Chrome for WebView cases.

This will not fully fix issue 977231 as that happens on ARM as well, but
this was just noticed via inspection.

Bug: chromium:781095, chromium:977231
Change-Id: If6dcc0ba776f82e8f20a50e6074822fb21a05aff
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/228300
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>
Reviewed-by: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

HalCanary/skia-hc,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,HalCanary/skia-hc,google/skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc