Introduce test for SVE support

When SVE extension is enabled, test that it correctly performs simple
operations.

Generating SVE instructions requires O3 compilation optimization. Since
the build structure does not allow compilation flag modification for
specific files, the function testing SVE support has been pre-compiled
and added as an assembly file.

Change-Id: Id9ba7d9e1de9bcbae3065cad2dd3e1dbe87ef03a
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>