Description:
------------
When using PHP SAPI and values have been added to the global $_SERVER variable, shutdown segfaults in zend_gc. If I remove the setting of the global variables it doesn't seg fault.
This is possibly not a fault the SAPI, but I've been unable to resolve, removing the destroy and free commands in shutdown function doesn't stop it from segfaulting.

Reproduce code:
---------------
The entire source code file is available at https://crispycrisp.org/php.txt this is the function that causes a segfault in shutdown if it has been called:
void php_set_superglobal_server(char *name, char *val)
{
    zend_first_try {
		HashTable* locals = &EG(symbol_table);

        zval *type;

        /* Fetch $_SERVER from the global scope */
        zend_hash_find(locals, "_SERVER", sizeof("_SERVER"),
                                                     (void**)&SERVER);

        ALLOC_INIT_ZVAL(type);
        ZVAL_STRING(type, val, 1);
        ZEND_SET_SYMBOL(Z_ARRVAL_PP(SERVER), name, type);
    } zend_end_try();
}

Expected result:
----------------
No segfault

Actual result:
--------------
==17605== Thread 2:
==17605== Invalid read of size 4
==17605==    at 0x43B4BB9: gc_remove_zval_from_buffer (zend_gc.h:189)
==17605==    by 0x438E18F: _zval_ptr_dtor (zend_execute_API.c:434)
==17605==    by 0x43A4C7D: zend_hash_destroy (zend_hash.c:526)
==17605==    by 0x804A88A: php_shutdown (php.c:143)
==17605==    by 0x804A955: php (php.c:168)
==17605==    by 0x8049D94: parsing_request (handler.c:180)
==17605==    by 0x80496FE: handle (handler.c:25)
==17605==    by 0x4032F3A: start_thread (in /lib/libpthread-2.7.so)
==17605==    by 0x4793BED: clone (in /lib/libc-2.7.so)
==17605==  Address 0x1c is not stack'd, malloc'd or (recently) free'd
==17605==
==17605== Process terminating with default action of signal 11 (SIGSEGV)
==17605==  Access not within mapped region at address 0x1C
==17605==    at 0x43B4BB9: gc_remove_zval_from_buffer (zend_gc.h:189)
==17605==    by 0x438E18F: _zval_ptr_dtor (zend_execute_API.c:434)
==17605==    by 0x43A4C7D: zend_hash_destroy (zend_hash.c:526)
==17605==    by 0x804A88A: php_shutdown (php.c:143)
==17605==    by 0x804A955: php (php.c:168)
==17605==    by 0x8049D94: parsing_request (handler.c:180)
==17605==    by 0x80496FE: handle (handler.c:25)
==17605==    by 0x4032F3A: start_thread (in /lib/libpthread-2.7.so)
==17605==    by 0x4793BED: clone (in /lib/libc-2.7.so)