Description:
------------
Stubs who's content before the __HALT_COMPILER(); registers between 1007 - 1023 
bytes (or an interval thereof) will force the function phar_open_from_fp() to 
incorrectly throw an MAPPHAR_ALLOC_FAIL() or:

Fatal error: Uncaught exception 'UnexpectedValueException' with message 'internal 
corruption of phar "xxx/test.phar" (__HALT_COMPILER(); not found)' in 
xxx/test.php:5

This is due to an incorrect index in the memmove() call inside the function that 
shifts the buffer to inspect the contents for the __HALT_COMPILER() token.

THis bug is exposed when opening a phar and iterating the contents.

Attached is a sample phar, test script, and patch

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

$phar = __DIR__ . '/test.phar';

foreach (new RecursiveIteratorIterator(new Phar($phar, null, 'test.phar')) as $item) {
    echo $item . PHP_EOL;
}

?>


Expected result:
----------------
Iterate the results.

Actual result:
--------------
Fatal error: Uncaught exception 'UnexpectedValueException' with message 'internal 
corruption of phar "xxx/test.phar" (__HALT_COMPILER(); not found)' in 
xxx/test.php:5