Modify files in install_xpu_headers only if they changes

[PawelSwider2000]

Observed that recompilations are triggered by updating files by install_xpu_headers.py script. Turns out that script does not change the files in any way but rewriting the same content into files updating their timestamp causing multiple dependent files to recompile.

This PR makes sure that install_xpu_headers.py changes or creates files only when content should change. This allow to speedup recompilations several times, by my experience from few minutes to few seconds.

This fixes: #2093

[guangyey]

LGTM.

[guangyey]

Thanks!

[Copilot]

Pull Request Overview

This PR optimizes the install_xpu_headers.py script to avoid unnecessary file modifications that trigger recompilations. The script now only writes files when their content actually changes, preventing timestamp updates that cause dependent files to recompile unnecessarily.

• Adds content comparison logic to prevent unnecessary file writes
• Implements binary file comparison for copied files to detect actual changes
• Adds conditional writing for both header files and CMake configuration files

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[guangyey]

Build pass, irrelevant error.