Adds generating binary versions of vmov for moves between floating
point registers, in the integrated ARM assembler.

Also adds simple lit test. Also simplifies the lit test for push/pop
(which had to be changed anyway since it included vmov instructions as
well).

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4334
R=eholk@chromium.org, jpp@chromium.org

Review URL: https://codereview.chromium.org/1645683003 .