fix chr() range check

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinFunctions.java

@@ -449,7 +449,7 @@ public abstract static class ChrNode extends PythonBuiltinNode {
         @TruffleBoundary
         @Specialization
         public String charFromInt(int arg) {
-            if (arg >= 0 && arg < 1114111) {
+            if (arg >= 0 && arg <= 1114111) {
                 return Character.toString((char) arg);
             } else {
                 throw raise(ValueError, "chr() arg not in range(0x110000)");