Unit tests: enable comprehensive heap poisoning checks

tools/unit-test-app/sdkconfig

@@ -269,6 +269,13 @@ CONFIG_TIMER_TASK_STACK_DEPTH=2048
 CONFIG_TIMER_QUEUE_LENGTH=10
 # CONFIG_FREERTOS_DEBUG_INTERNALS is not set
 
+#
+# Heap memory debugging
+#
+# CONFIG_HEAP_POISONING_DISABLED is not set
+# CONFIG_HEAP_POISONING_LIGHT is not set
+CONFIG_HEAP_POISONING_COMPREHENSIVE=y
+
 #
 # Log output
 #