Added regression test for lastIndexOf

Added regression (smoke test) for usage of long strings with lastIndexOf to detect future performance degredations.

Author: jasigal

regression/strings-smoke-tests/java_last_index_of2/test.desc

@@ -0,0 +1,7 @@
+CORE
+test_last_index_of2.class
+--refine-strings
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--

regression/strings-smoke-tests/java_last_index_of2/test_last_index_of2.class

@@ -0,0 +1,8 @@
+public class test_last_index_of2
+{
+   public static void main(String[] args)
+   {
+      String letters = "automatictestcasegenerationatdiffblue";
+      assert(letters.lastIndexOf("diffblue", 25)==-1);
+   }
+}