GHA: Improve Windows builds: MinGW/GCC with LTO, D3D12, ANGLE #756

Job	Run time
🧪 Unit tests	3m 1s
cache-env	1s
⚙️ Static checks	8s
🍎 macOS / Editor (x86_64, release)	2m 47s
🍎 macOS / Editor (arm64, release)	3m 28s
🐧 Linux / Editor (x86_64, release)	14m 18s
🔌 GDExtension / 🐧 Linux (x86_64, release)	21s
🪟 Windows / Editor (x86_64, release)	48m 56s
🐧 Linux / Template (x86_64, release)	9m 26s
🔌 GDExtension / 🐧 Linux (x86_64, debug)	29s
🐧 Linux / Editor .NET (x86_64, release)	16m 15s
🔌 GDExtension / 🪟 Windows (x86_64, release)	2m 16s
🔌 GDExtension / 🪟 Windows (x86_64, debug)	1m 38s
🔌 GDExtension / 🍎 macOS (universal, release)	50s
🔌 GDExtension / 🍎 macOS (universal, debug)	52s
🔌 GDExtension / 📦 Package extension	28s
🍎 macOS / Make macOS Bundles (tmp-macos, false, true)	45s
🪟 Windows / .NET assembly for ${{ matrix.opts.arch }}	0s
	1h 45m 59s

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