Added regression test for the prefix iterator in for loop

This has been fixed, but previously it would complain about whitespace
before the +

regression/cpp-linter/prefix-increment/main.cpp

@@ -0,0 +1,14 @@
+/*******************************************************************\
+
+Module: Lint Examples
+
+Author: Thomas Kiley, thomas@diffblue.com
+
+\*******************************************************************/
+
+static void fun()
+{
+  for(int i=0; i<10; ++i)
+  {
+  }
+}

regression/cpp-linter/prefix-increment/test.desc

@@ -0,0 +1,6 @@
+CORE
+main.cpp
+
+^EXIT=0$
+^SIGNAL=0$
+--