Adding test for exception throwing in String.format

This is marked as knownbug as it does not work at the moment.

Author: romainbrenguier

regression/strings-smoke-tests/java_format4/test.class

@@ -0,0 +1,8 @@
+KNOWNBUG
+test.class
+--refine-strings --string-max-length 20
+^EXIT=10$
+^SIGNAL=0$
+^\[.*assertion.1\].* line 8.* SUCCESS$
+^\[.*assertion.2\].* line 13.* FAILURE$
+--

regression/strings-smoke-tests/java_format4/test.desc

@@ -0,0 +1,17 @@
+public class test
+{
+    public static String main(String str)
+    {
+        try
+        {
+            String s = String.format("%s %s", "a");
+            assert(false);
+            return s;
+        }
+        catch(java.util.IllegalFormatException e)
+        {
+            assert(false);
+            return str;
+        }
+    }
+}