Some tests were recently added to test-simulator-arm.cc, however this file is
meant for tests that are specific to the simulator and therefore are not written
to work on hardware. While this sounds surprising, the reason is that our simulation
of synchronisation instructions is more conservative than on hardware.

To make this more clear, this patch renames the "test-simulator-arm{,64}.cc"
files to "test-sync-primitives-arm{,64}.cc", and moves the vneg and vabs tests
into "test-assembler-arm.cc" which is were tests that are garanteed to work in
either native or simulated environments live.

Finally, take the opportunity to share a little bit of code.

Bug: v8:6963
Change-Id: Ifb85d3671c823b9bba73d09f419536b089a4e87c
Reviewed-on: https://chromium-review.googlesource.com/749387Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#49073}