Focus -Wno-over-aligned to just 32-bit x86 Android. (2)

I've even found the code that's making this happen, just don't know why.
I've added a test to assert that it's safe to assume malloc() is 8-byte aligned.

Test should compile this time.

CQ_INCLUDE_TRYBOTS=master.client.skia.android:Test-Android-Clang-NexusPlayer-CPU-Moorefield-x86-Release-GN_Android-Trybot

Change-Id: I48714b99670c20704adf4f7f216da0d60d7d9bcd
Reviewed-on: https://skia-review.googlesource.com/2662
Reviewed-on: https://skia-review.googlesource.com/2703
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed