Description:
------------
The fix for bug https://bugs.php.net/bug.php?id=60494 ignores the ICONV_MIME_DECODE_CONTINUE_ON_ERROR flag and false the parse.   Prior to 7.1.22 parsing headers with erogenous characters worked fine, or as good as you were going to get anyway.

The previous behavior should be respected (ignoring these broken chars) when ICONV_MIME_DECODE_CONTINUE_ON_ERROR is set, as per the php manual.

Test script:
---------------
<?php

$string = <<<EOF
Feedback-ID: 014a93e3-1f5e-4df6-b347-6b59f0f746b8:b5891053-55d1-45bc-a0b5-47a7a9b59687:email:epslh1�
EOF;

$headers = iconv_mime_decode_headers($string, ICONV_MIME_DECODE_CONTINUE_ON_ERROR);

print_r($headers);

Expected result:
----------------
Array
(
    [Feedback-ID] => 014a93e3-1f5e-4df6-b347-6b59f0f746b8:b5891053-55d1-45bc-a0b5-47a7a9b59687:email:epslh1
)

Actual result:
--------------
false