Fix pc offset calculation for stack traces

Use the correct address of the code object to calculate the offset from the code object start to a pc for an optimized frame.

BUG=
TEST=

Review URL: http://codereview.chromium.org//6759052

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7468 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/frames.h

@@ -430,7 +430,7 @@ class FrameSummary BASE_EMBEDDED {
   Handle<Object> receiver() { return receiver_; }
   Handle<JSFunction> function() { return function_; }
   Handle<Code> code() { return code_; }
-  Address pc() { return reinterpret_cast<Address>(*code_) + offset_; }
+  Address pc() { return code_->address() + offset_; }
   int offset() { return offset_; }
   bool is_constructor() { return is_constructor_; }