Increased memory limit for ext/standard/tests/streams/bug78902

Reducing the memory limit below the current memory has probably not
been the intention of this test.

Author: pvandommelen

ext/standard/tests/streams/bug78902.phpt

@@ -1,14 +1,14 @@
 --TEST--
 Bug #78902: Memory leak when using stream_filter_append
 --INI--
-memory_limit=512k
+memory_limit=2M
 --FILE--
 <?php
 
 /** create temporary file 2mb file */
 $tmp_file_name = tempnam(sys_get_temp_dir(), 'test_');
 $fp = fopen($tmp_file_name, 'w+');
-$size = 1024 * 1024 * 2; // 2mb
+$size = 1024 * 1024 * 4; // 4mb, larger than the memory limit
 $chunk = 1024;
 while ($size > 0) {
     fputs($fp, str_pad('', min($chunk,$size)));