Add regression test for null instanceof.

Author: Matthias Güdemann

regression/cbmc-java/instanceof8/InstanceOf8.class

@@ -0,0 +1,14 @@
+public class InstanceOf8 {
+  public static boolean test(Integer i) {
+    if (i instanceof Integer) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+  public static void main(String[] args)
+  {
+    assert(!test(null));
+    assert(test(new Integer(1)));
+  }
+}

regression/cbmc-java/instanceof8/InstanceOf8.java

@@ -0,0 +1,7 @@
+CORE
+InstanceOf8.class
+
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--