Description:
------------
A simple PHPUnit test case:

```
class LeakTest extends \PHPUnit\Framework\TestCase
{
    /**
     * @expectedException \RuntimeException
     */
    public function testLeak()
    {
        throw new \RuntimeException();
    }
}
```

leaks when run under Valgrind:

USE_ZEND_ALLOC=0 valgrind --leak-check=full $(phpenv which php) ./phpunit

(phpunit runs `PHPUnit\TextUI\Command::main(false)` to ensure clean shutdown without exit()).

Tested this on 7.1.17 (ZTS/NTS, DEBUG/Release)

* release versions (ZTS and NTS) leak;
* debug versions (ie, built with --enable-debug) do NOT leak.

Test script:
---------------
https://github.com/sjinks/php-memory-leak-on-exception

Expected result:
----------------
$ USE_ZEND_ALLOC=0 valgrind --leak-check=full $(phpenv which php) ./phpunit
==13709== Memcheck, a memory error detector
==13709== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==13709== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==13709== Command: /home/volodymyr/.phpenv/versions/7.1.17-zts-debug/bin/php ./phpunit
==13709==
PHPUnit 7.1.5 by Sebastian Bergmann and contributors.

Runtime:       PHP 7.1.17
Configuration: /home/volodymyr/work/github/php-leaks/phpunit.xml

.                                                                   1 / 1 (100%)

Time: 2.6 seconds, Memory: 0.00MB

OK (1 test, 1 assertion)
OK
==13709==
==13709== HEAP SUMMARY:
==13709==     in use at exit: 5,519 bytes in 41 blocks
==13709==   total heap usage: 111,228 allocs, 111,187 frees, 18,208,664 bytes allocated
==13709==
==13709== LEAK SUMMARY:
==13709==    definitely lost: 0 bytes in 0 blocks
==13709==    indirectly lost: 0 bytes in 0 blocks
==13709==      possibly lost: 0 bytes in 0 blocks
==13709==    still reachable: 5,519 bytes in 41 blocks
==13709==         suppressed: 0 bytes in 0 blocks
==13709== Reachable blocks (those to which a pointer was found) are not shown.
==13709== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==13709==
==13709== For counts of detected and suppressed errors, rerun with: -v
==13709== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

Actual result:
--------------
$ USE_ZEND_ALLOC=0 valgrind --leak-check=full $(phpenv which php) ./phpunit
==13677== Memcheck, a memory error detector
==13677== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==13677== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==13677== Command: /home/volodymyr/.phpenv/versions/7.1.17-zts-release/bin/php ./phpunit
==13677== 
PHPUnit 7.1.5 by Sebastian Bergmann and contributors.

Runtime:       PHP 7.1.17
Configuration: /home/volodymyr/work/github/php-leaks/phpunit.xml

.                                                                   1 / 1 (100%)

Time: 1.27 seconds, Memory: 0.00MB

OK (1 test, 1 assertion)
OK
==13677== 
==13677== HEAP SUMMARY:
==13677==     in use at exit: 1,774 bytes in 33 blocks
==13677==   total heap usage: 81,556 allocs, 81,523 frees, 14,308,544 bytes allocated
==13677==
==13677== 72 bytes in 1 blocks are definitely lost in loss record 29 of 33
==13677==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==13677==    by 0x69DB58: __zend_malloc (zend_alloc.c:2838)
==13677==    by 0x70C5F7: zend_objects_new (zend_objects.c:171)
==13677==    by 0x6D1DE0: _object_and_properties_init (zend_API.c:1295)
==13677==    by 0x77ADD5: ZEND_NEW_SPEC_UNUSED_HANDLER (zend_vm_execute.h:27938)
==13677==    by 0x71D4A2: execute_ex (zend_vm_execute.h:429)
==13677==    by 0x781334: zend_execute (zend_vm_execute.h:474)
==13677==    by 0x6CEED1: zend_execute_scripts (zend.c:1482)
==13677==    by 0x65C8EF: php_execute_script (main.c:2577)
==13677==    by 0x783935: do_cli (php_cli.c:993)
==13677==    by 0x250652: main (php_cli.c:1381)
==13677==
==13677== LEAK SUMMARY:
==13677==    definitely lost: 72 bytes in 1 blocks
==13677==    indirectly lost: 0 bytes in 0 blocks
==13677==      possibly lost: 0 bytes in 0 blocks
==13677==    still reachable: 1,702 bytes in 32 blocks
==13677==         suppressed: 0 bytes in 0 blocks
==13677== Reachable blocks (those to which a pointer was found) are not shown.
==13677== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==13677==
==13677== For counts of detected and suppressed errors, rerun with: -v
==13677== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)