Mark assert() as INDIRECT_VAR_ACCESS

I don't like this... we may want to detect "obviously not string"
operands by checking for the result of a comparison instruction.

Author: nikic

Zend/tests/assert/indirect_var_access_misoptimization.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Misoptimization when variable is modified by assert()
+--INI--
+zend.assertions=1
+--FILE--
+<?php
+
+function test() {
+    $i = 0;
+    assert('$i = new stdClass');
+    $i += 1;
+    var_dump($i);
+}
+test();
+
+?>
+--EXPECTF--
+Notice: Object of class stdClass could not be converted to int in %s on line %d
+int(2)

ext/opcache/Optimizer/zend_cfg.c

@@ -308,6 +308,8 @@ int zend_build_cfg(zend_arena **arena, const zend_op_array *op_array, uint32_t b
 							flags |= ZEND_FUNC_INDIRECT_VAR_ACCESS;
 						} else if (zend_string_equals_literal(Z_STR_P(zv), "get_defined_vars")) {
 							flags |= ZEND_FUNC_INDIRECT_VAR_ACCESS;
+						} else if (zend_string_equals_literal(Z_STR_P(zv), "assert")) {
+							flags |= ZEND_FUNC_INDIRECT_VAR_ACCESS;
 						} else if (zend_string_equals_literal(Z_STR_P(zv), "func_num_args")) {
 							flags |= ZEND_FUNC_VARARG;
 						} else if (zend_string_equals_literal(Z_STR_P(zv), "func_get_arg")) {