Fix an off-by-one error in the stack frame iteration.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 3102b7491b1a93005e3035029b184af23adcda02..bef35bcaaf436bfe5f11abe3d3f5716d5cbf404d 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -7113,8 +7113,8 @@ intptr_t Code::ExtractIcDataArraysAtCalls(
 
 
 RawStackmap* Code::GetStackmap(uword pc, Array* maps, Stackmap* map) const {
-  // This code is used only during iterating frames during a GC and hence
-  // it should not in turn start a GC.
+  // This code is used during iterating frames during a GC and hence it
+  // should not in turn start a GC.
   NoGCScope no_gc;
   if (stackmaps() == Array::null()) {
     // No stack maps are present in the code object which means this