Service: Add a new SLIH test

This patch adds a new SLIH test Partition and new IRQ test suite.
The test logic for SLIH - previously IRQ test - is simplified a lot
as well.

This service is intended to replace the tfm_irq_test_1 service.

Change-Id: Ie319bd57121f73125819bcfbb80943cc557533d9
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
10 files changed