Description:
------------
Hi,

I've just noticed a change in chunk_split behaviour in 4.3.11 which breaks my application.

Regards,
  Jocelyn

Reproduce code:
---------------
With the following script :

$test=chunk_split('test',10,"|end");
echo $test;

In 4.3.10 :

test|end

In 4.3.11 :

test

(ie "string end" in 4.3.10 is inserted at the end of the "string body" even if the word is smaller than the chunklen)

However if the word is greater than the chunklen 4.3.10 and 4.3.11 behaves the same.

Expected result:
----------------
test|end

Actual result:
--------------
test