Test only works with simplification enabled

... and simplification is only performed for byte_extract_little_endian.

regression/cbmc/scanf1/big-endian.desc

@@ -0,0 +1,8 @@
+KNOWNBUG
+main.i
+--big-endian
+^EXIT=10$
+^SIGNAL=0$
+^\*\* 8 of 8 failed
+--
+^warning: ignoring

regression/cbmc/scanf1/main.c → regression/cbmc/scanf1/main.i

@@ -1,6 +1,3 @@
-#include <stdio.h>
-#include <assert.h>
-
 int main(void)
 {
   char c=0;
@@ -23,14 +20,14 @@ int main(void)
   __CPROVER_scanf("%p", &p);
   __CPROVER_scanf("%s", buffer);
 
-  assert(c==0); // may fail
-  assert(si==0); // may fail
-  assert(i==0); // may fail
-  assert(f==0); // may fail
-  assert(d==0); // may fail
-  assert(li==0); // may fail
-  assert(p==0); // may fail
-  assert(buffer[0]==0); // may fail
+  __CPROVER_assert(c == 0, "may fail");
+  __CPROVER_assert(si == 0, "may fail");
+  __CPROVER_assert(i == 0, "may fail");
+  __CPROVER_assert(f == 0, "may fail");
+  __CPROVER_assert(d == 0, "may fail");
+  __CPROVER_assert(li == 0, "may fail");
+  __CPROVER_assert(p == 0, "may fail");
+  __CPROVER_assert(buffer[0] == 0, "may fail");
 
   return 0;
 }

regression/cbmc/scanf1/no-simplify.desc

@@ -0,0 +1,8 @@
+KNOWNBUG
+main.i
+--little-endian --no-simplify
+^EXIT=10$
+^SIGNAL=0$
+^\*\* 8 of 8 failed
+--
+^warning: ignoring

regression/cbmc/scanf1/test.desc

@@ -1,6 +1,6 @@
 CORE
-main.c
-
+main.i
+--little-endian
 ^EXIT=10$
 ^SIGNAL=0$
 ^\*\* 8 of 8 failed