Remove dead_stores HashSet and clean up pass #12795

Job	Run time
Windows 11-arm/Visual C++ (btest test-basic test-tool)	17m 3s
Windows 2025/Visual C++ 2022 (check)	27m 25s
Windows 2025/Visual C++ 2022 (test-bundled-gems)	25m 30s
Windows 2022/Visual C++ 2022 (check)	25m 16s
Windows result	3s
	1h 35m 17s

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