Add support to connect Arm Development Studio IDE to FVP on local runs.

This patch adds the environment variable "connect_debugger" to CI:

     * When connect_debugger == 0 (default), CI will work as usual.
     * When connect_debugger == 1, CI will
       - Call FVP with the -S flag enabled, so it can connect
       	 to ARM DS IDE for debugging sessions.
       - Set test_run variable to 1, overriding any manual
         setting for this variable.
       - Build TF-A with SPIN_ON_BL1 flag enabled.

Change-Id: I300b9babc28c0d4752bf3352ca3599da14f34edb
Signed-off-by: Javier Almansa Sobrino <javier.almansasobrino@arm.com>
3 files changed