Fix crash in array_filter/array_map with a bad function

interp only

hphp/runtime/vm/bytecode.cpp

@@ -5900,6 +5900,7 @@ inline void OPTBLD_INLINE VMExecutionContext::iopFPushCtorD(PC& pc) {
 }
 
 inline void OPTBLD_INLINE VMExecutionContext::iopDecodeCufIter(PC& pc) {
+  PC origPc = pc;
   NEXT();
   DECODE_IA(itId);
   DECODE(Offset, offset);
@@ -5922,7 +5923,7 @@ inline void OPTBLD_INLINE VMExecutionContext::iopDecodeCufIter(PC& pc) {
                                      false);
 
   if (f == nullptr) {
-    pc += offset;
+    pc = origPc + offset;
   } else {
     cit.setFunc(f);
     if (obj) {

hphp/test/slow/array_functions/bad_array_filter.php

@@ -0,0 +1,4 @@
+<?php
+
+error_reporting(-1);
+var_dump(array_filter(array(1,2,3), 'fizzle'));

hphp/test/slow/array_functions/bad_array_filter.php.expectf

@@ -0,0 +1,2 @@
+HipHop Warning: array_filter() expects parameter 2 to be a valid callback in %s/test/slow/array_functions/bad_array_filter.php on line 4
+NULL