[HIPIFY][Perl][fix] Streamline C++ File I/O and Output Streams in the hipify-perl generator

* Modernized file I/O by replacing the dynamic `unique_ptr` heap allocation with a standard stack-allocated `ofstream`.
* The generated `hipify-perl` is unchanged

**Key Changes:**
* Updated all internal helper functions to accept a standard `ostream &` instead of `unique_ptr<ostream> &`
* Completely eliminated the verbose `*streamPtr.get()` boilerplate throughout the generator
* Improved overall C++ readability, safety, and resource management

Author: emankov