rdinfra: add 'rdinfra' platform test scripts

The new 'RD' infrastructure/enterprise platforms can reuse all the tests
under the SGI platforms. So add initial set of test run scripts that
reuse all the run scripts for the SGI platform.

Change-Id: I0687205966e502239394b7e9dee5a8468d2f34af
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>