msg_socket: fix msg_on_socket alignment issue
msg_socket: fix msg_on_socket alignment issue

Instead of using unaligned memory. Allocate aligned memory and copy into it, we
were already doing an clone. There should be no overhead for this new
approach.

BUG=chromium:900962
TEST=build and run

Change-Id: I011d4c93a872d7d285e8898ff332f3ee1ef104a9
Reviewed-on: https://chromium-review.googlesource.com/1344225
Commit-Ready: Jingkui Wang <c645f91f31b7cead6dc73127db4670945d892e95@google.com>
Tested-by: Jingkui Wang <c645f91f31b7cead6dc73127db4670945d892e95@google.com>
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm