[debug] load correct stack slot for frame details.

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index 18abeef1f32e8399863a05fcaa7b99d81e19ece3..e02a58212176911f119d25499502955e7db9f7bc 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -562,7 +562,8 @@ RUNTIME_FUNCTION(Runtime_GetFrameDetails) {
     // Use the value from the stack.
     if (ScopeInfo::VariableIsSynthetic(scope_info->LocalName(i))) continue;
     locals->set(local * 2, scope_info->LocalName(i));
-    Handle<Object> value = frame_inspector.GetExpression(i);
+    Handle<Object> value =
+        frame_inspector.GetExpression(scope_info->StackLocalIndex(i));
     // TODO(yangguo): We convert optimized out values to {undefined} when they
     // are passed to the debugger. Eventually we should handle them somehow.
     if (value->IsOptimizedOut()) value = isolate->factory()->undefined_value();