feat(ls64): add a test for 64byte loads/stores instructions

This patch adds a test to verify the 64 byte load and store
instructions introduced by FEAT_LS64.
The test primarily executes instructions:
1. LD64B
2. ST64B
and ensures that the NS-EL2 has no dependency on EL3 while
running them.

Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: I7a4ca0ee4a2c18bf0de030c72e35eb218bc6364c
diff --git a/tftf/tests/tests-cpu-extensions.xml b/tftf/tests/tests-cpu-extensions.xml
index 0f8d0f6..22ae510 100644
--- a/tftf/tests/tests-cpu-extensions.xml
+++ b/tftf/tests/tests-cpu-extensions.xml
@@ -35,6 +35,7 @@
     <testcase name="PMUv3 cycle counter functional in NS" function="test_pmuv3_cycle_works_ns" />
     <testcase name="PMUv3 event counter functional in NS" function="test_pmuv3_event_works_ns" />
     <testcase name="PMUv3 SMC counter preservation" function="test_pmuv3_el3_preserves" />
+    <testcase name="LS64 support" function="test_ls64_instructions" />
   </testsuite>
 
   <testsuite name="ARM_ARCH_SVC" description="Arm Architecture Service tests">