Description:
------------
The code below causes two small memleaks.

Reproduce code:
---------------
<?php
function err($errno, $errstr, $errfile, $errline) {
    throw new Exception($errstr);
}
set_error_handler("err");

function foo() {
    $a = array("aaa");
    foreach ($a as $o) {
        //$this->prop[$a] = foo($undef2); //no leak
        //$this->prop["aa"] = foo($undef2); //no leak
        $this->prop[$a[0]] = foo($undef2); //leak
    }
}

try {
    foo();
} catch (Exception $e) {
    var_dump($e->getMessage());
}
?>

Actual result:
--------------
==10584== 4 bytes in 1 blocks are indirectly lost in loss record 1 of 2
==10584==    at 0x401C6CE: malloc (vg_replace_malloc.c:149)
==10584==    by 0x82995DF: _emalloc (zend_alloc.c:2231)
==10584==    by 0x8299885: _estrndup (zend_alloc.c:2353)
==10584==    by 0x82B210F: _zval_copy_ctor_func (zend_variables.c:120)
==10584==    by 0x831694C: _zval_copy_ctor (zend_variables.h:45)
==10584==    by 0x82D9FAB: ZEND_ADD_ARRAY_ELEMENT_SPEC_CONST_UNUSED_HANDLER (zend_vm_execute.h:3562)
==10584==    by 0x82DA140: ZEND_INIT_ARRAY_SPEC_CONST_UNUSED_HANDLER (zend_vm_execute.h:3609)
==10584==    by 0x82D31F8: execute (zend_vm_execute.h:92)
==10584==    by 0x82D371A: zend_do_fcall_common_helper_SPEC (zend_vm_execute.h:234)
==10584==    by 0x82D6614: ZEND_DO_FCALL_SPEC_CONST_HANDLER (zend_vm_execute.h:1681)
==10584==    by 0x82D31F8: execute (zend_vm_execute.h:92)
==10584==    by 0x82B3E37: zend_execute_scripts (zend.c:1134)
==10584==    by 0x826A9BC: php_execute_script (main.c:1790)
==10584==    by 0x831A5B5: main (php_cli.c:1127)
==10584==
==10584==
==10584== 20 (16 direct, 4 indirect) bytes in 1 blocks are definitely lost in loss record 2 of 2
==10584==    at 0x401C6CE: malloc (vg_replace_malloc.c:149)
==10584==    by 0x82995DF: _emalloc (zend_alloc.c:2231)
==10584==    by 0x82D9F5D: ZEND_ADD_ARRAY_ELEMENT_SPEC_CONST_UNUSED_HANDLER (zend_vm_execute.h:3559)
==10584==    by 0x82DA140: ZEND_INIT_ARRAY_SPEC_CONST_UNUSED_HANDLER (zend_vm_execute.h:3609)
==10584==    by 0x82D31F8: execute (zend_vm_execute.h:92)
==10584==    by 0x82D371A: zend_do_fcall_common_helper_SPEC (zend_vm_execute.h:234)
==10584==    by 0x82D6614: ZEND_DO_FCALL_SPEC_CONST_HANDLER (zend_vm_execute.h:1681)
==10584==    by 0x82D31F8: execute (zend_vm_execute.h:92)
==10584==    by 0x82B3E37: zend_execute_scripts (zend.c:1134)
==10584==    by 0x826A9BC: php_execute_script (main.c:1790)
==10584==    by 0x831A5B5: main (php_cli.c:1127)