Fix assert abstraction in sim

Assertions that are expected to fail under sim test, are now marked as such
using the macro ASSERT which allows to programmatically switch between normal
assert() behavior and captured assertion.

Assertion changes were moved to more appropriate owners and code duplication
was removed.

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/sim/mcuboot-sys/csupport/run.c b/sim/mcuboot-sys/csupport/run.c
index 91d779a..9b5e36e 100644
--- a/sim/mcuboot-sys/csupport/run.c
+++ b/sim/mcuboot-sys/csupport/run.c
@@ -10,6 +10,7 @@
 #include "flash_map/flash_map.h"
 
 #include "../../../boot/bootutil/src/bootutil_priv.h"
+#include "bootsim.h"
 
 #ifdef MCUBOOT_SIGN_EC256
 #include "../../../ext/tinycrypt/lib/include/tinycrypt/ecc_dsa.h"