Description:
------------
3rd call on igbinary_unserialize ends up with segmentation fault. Test attached.

Test script:
---------------
--TEST--
igbinary_unserialize causes segfault on 3rd call for objects with dynamic property
--FILE--
<?php
class Obj
{
    public $bar = "test";
}
$value = new Obj();
$value->i = 1;

$igb = igbinary_serialize($value);
for ($i=0; $i<=30; $i++)
{
    // This might segfault at the third attempt
    echo igbinary_unserialize($igb)->bar . PHP_EOL;
}
--EXPECT--
test
test
test


Expected result:
----------------
test
test
test


Actual result:
--------------
test
test
test
Segmentation fault

Termsig=11


Backtrace:

Program received signal SIGSEGV, Segmentation fault.
0x000000000092af96 in _zend_is_inconsistent (ht=0x0, file=0xf4eea7 "/usr/src/php/Zend/zend_hash.c", line=1981) at /usr/src/php/Zend/zend_hash.c:47
47              if ((ht->u.flags & HASH_MASK_CONSISTENCY) == HT_OK) {
(gdb) bt
#0  0x000000000092af96 in _zend_is_inconsistent (ht=0x0, file=0xf4eea7 "/usr/src/php/Zend/zend_hash.c", line=1981) at /usr/src/php/Zend/zend_hash.c:47
#1  0x0000000000930c71 in zend_hash_find (ht=0x0, key=0x7ffff2202c00) at /usr/src/php/Zend/zend_hash.c:1981
#2  0x00007ffff1ffb9ed in igbinary_unserialize_array (igsd=0x7fffffffab50, t=igbinary_type_array8, z=0x7ffff2214141, flags=1) at /usr/src/php/ext/ext-php7-igbinary-rc1/igbinary.c:2018
#3  0x00007ffff1ffc4b4 in igbinary_unserialize_object (igsd=0x7fffffffab50, t=igbinary_type_array8, z=0x7ffff2214140, flags=0) at /usr/src/php/ext/ext-php7-igbinary-rc1/igbinary.c:2224
#4  0x00007ffff1ffcbbf in igbinary_unserialize_zval (igsd=0x7fffffffab50, z=0x7ffff2214140, flags=0) at /usr/src/php/ext/ext-php7-igbinary-rc1/igbinary.c:2371
#5  0x00007ffff1ff813d in igbinary_unserialize (buf=0x7ffff2258a98 "", buf_len=27, z=0x7ffff2214140) at /usr/src/php/ext/ext-php7-igbinary-rc1/igbinary.c:455
#6  0x00007ffff1ff81e6 in zif_igbinary_unserialize (execute_data=0x7ffff2214190, return_value=0x7ffff2214140) at /usr/src/php/ext/ext-php7-igbinary-rc1/igbinary.c:478
#7  0x000000000097570e in ZEND_DO_ICALL_SPEC_HANDLER () at /usr/src/php/Zend/zend_vm_execute.h:586
#8  0x000000000097513a in execute_ex (ex=0x7ffff2214030) at /usr/src/php/Zend/zend_vm_execute.h:414
#9  0x000000000097524f in zend_execute (op_array=0x7ffff227e000, return_value=0x0) at /usr/src/php/Zend/zend_vm_execute.h:458
#10 0x000000000091a7c9 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /usr/src/php/Zend/zend.c:1427
#11 0x000000000088d472 in php_execute_script (primary_file=0x7fffffffe2a0) at /usr/src/php/main/main.c:2494
#12 0x00000000009da0e8 in do_cli (argc=2, argv=0x12c3590) at /usr/src/php/sapi/cli/php_cli.c:974
#13 0x00000000009db08c in main (argc=2, argv=0x12c3590) at /usr/src/php/sapi/cli/php_cli.c:1344