Add test for checking symbolic comparisons

Author: Thomas Kiley

regression/goto-analyzer/intervals_simple-loops/main.c

@@ -0,0 +1,15 @@
+#include <assert.h>
+const int g_N = 2;
+
+void main(void)
+{
+  for(int i = 0; i < g_N; i++)
+  {
+    assert(0);
+  }
+
+  for(int j = 4; j >= g_N; j--)
+  {
+    assert(0);
+  }
+}

regression/goto-analyzer/intervals_simple-loops/test.desc

@@ -0,0 +1,11 @@
+CORE
+main.c
+--intervals
+^EXIT=0$
+^SIGNAL=0$
+\[main\.assertion\.1\] line 8 assertion 0: UNKNOWN
+\[main\.assertion\.2\] line 13 assertion 0: UNKNOWN
+--
+--
+Test comparision between two symbols does not mark the
+result as bottom