Fix off-by-one error in DelimitedLineTokenizer on blank strings

There is currently a bug causing an ArrayIndexOutOfBoundsException
when trying to tokenize a blank string with more than two characters

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineTokenizer.java

@@ -211,7 +211,7 @@ public class DelimitedLineTokenizer extends AbstractLineTokenizer
         int start = offset;
         int len = count;
 
-        while ((start < (start + len)) && (chars[start] <= ' ')) {
+        while ((start < (start + len - 1)) && (chars[start] <= ' ')) {
             start++;
             len--;
         }