Optimize `AudioServer::_driver_process()` #20798

Job	Run time
📊 Static checks / Code style, file formatting, and docs	40s
🤖 Android / Template (target=template_release)	28m 46s
🍎 macOS / Editor (target=editor, tests=yes)	1h 0m 2s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	20m 56s
🍎 macOS / Template (target=template_release)	16m 26s
🏁 Windows / Editor (target=editor, tests=yes)	41m 42s
🌐 Web / Template w/o threads (target=template_release, threads=no)	21m 21s
🍏 iOS / Template (target=template_release)	28m 8s
🏁 Windows / Template (target=template_release)	28m 59s
🐧 Linux / Editor w/ Mono (target=editor)	35m 44s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	35m 53s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	31m 59s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	27m 56s
🐧 Linux / Template w/ Mono (target=template_release)	23m 5s
🐧 Linux / Minimal template (target=template_release, everything disabled)	13m 38s
🪲 Godot CPP / Build and test Godot CPP	6m 58s
	7h 2m 13s

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