tests: boot: test_mcuboot: Add test with asserts enabled

Chain-load images might behave differently comparing to the usual
standalone boot, as for example some peripheral initialization
might be done already.

Add an additional test with CONFIG_ASSERT=y as enabled asserts
could break up chain-loaded image.

Signed-off-by: Denis Mingulov <denis@mingulov.com>
diff --git a/tests/boot/test_mcuboot/testcase.yaml b/tests/boot/test_mcuboot/testcase.yaml
index 4359e68..fd01115 100644
--- a/tests/boot/test_mcuboot/testcase.yaml
+++ b/tests/boot/test_mcuboot/testcase.yaml
@@ -19,3 +19,9 @@
     integration_platforms:
       - frdm_k64f
       - nrf52840dk_nrf52840
+  boot.mcuboot.assert:
+    tags: mcuboot
+    platform_allow:
+      - b_u585i_iot02a
+    extra_configs:
+      - CONFIG_ASSERT=y