Description:
------------
The following poc causes a seg fault in php_var_export_ex.(run with `php -f poc.php`)

Stack dump:
---
==248221==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x000000bc961e bp 0x7fffeef12990 sp 0x7fffeef11d80 T0)
    #0 0xbc961d in php_var_export_ex (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbc961d)
    #1 0xbc5658 in php_array_element_export (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbc5658)
    #2 0xbca1be in php_var_export_ex (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbca1be)
    #3 0xbc5658 in php_array_element_export (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbc5658)
    #4 0xbca1be in php_var_export_ex (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbca1be)
    #5 0xbcd1a6 in zif_var_export (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xbcd1a6)
    #6 0x123c2d1 in execute_ex (/home/rxz226/php-src/bld_asan/sapi/cli/php+0x123c2d1)
    #7 0xdf5a2f in zend_call_function (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xdf5a2f)
    #8 0xe6de12 in zend_fcall_info_call (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xe6de12)
    #9 0xce8f9b in php_output_handler_op (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xce8f9b)
    #10 0xcea7df in php_output_stack_pop (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xcea7df)
    #11 0xce426e in php_output_end_all (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xce426e)
    #12 0xca8df5 in php_request_shutdown (/home/rxz226/php-src/bld_asan/sapi/cli/php+0xca8df5)
    #13 0x1281d33 in do_cli (/home/rxz226/php-src/bld_asan/sapi/cli/php+0x1281d33)
    #14 0x1282acb in main (/home/rxz226/php-src/bld_asan/sapi/cli/php+0x1282acb)
    #15 0x7f9d7b3e782f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #16 0x428a78 in _start (/home/rxz226/php-src/bld_asan/sapi/cli/php+0x428a78)
---

Test script:
---------------
<?                                for (   $GLOBALS =  $a      ;
                                  ;
                                                             (  $b   .  set_error_handler ( function () {                           for (  $GLOBALS [] =  $c  ;                           $d < 10 ;                           $d ++ )      list ( $a [] ,   $a  [ $e  ]  ) = array ()   ;                                       }
                               )  )  [ ob_start ( function () {                           $a [ $d ] <  var_export ( $GLOBALS [] = & $GLOBALS ,  list ( var_dump ( [] ) [ var_export ( $GLOBALS [] = $GLOBALS ,  $f  ) ]    ) = array () [ $$g ]  )   ;                            }
                               ) ]                                              ) ;