Test

Add `windows_legacy` opt-in backend #2149

Job	Run time
Linux (i686-unknown-linux-musl)	23s
Linux (x86_64-unknown-linux-musl)	28s
iOS Simulator	2m 10s
Tier 1 (ubuntu-24.04, 1.63)	22s
Tier 1 (ubuntu-24.04, stable)	18s
Tier 1 (ubuntu-24.04, nightly)	16s
WASI	27s
Tier 1 (windows-2022, beta)	47s
Tier 1 (ubuntu-24.04, beta)	17s
Tier 1 (windows-2022, 1.63)	59s
Sanitizer Linux (x86_64, ubuntu-24.04)	2m 46s
Sanitizer Linux (aarch64, ubuntu-24.04-arm)	2m 21s
OpenBSD VM	2m 28s
Tier 1 (macos-14, stable)	22s
FreeBSD VM	3m 13s
Tier 1 (windows-2022, stable)	1m 3s
Web with Atomics	1m 34s
Windows 7 (on Windows 10)	1m 48s
Windows (stable-x86_64-gnu)	3m 14s
Tier 1 (windows-2022, nightly)	54s
Windows (stable-i686-gnu)	49s
Cross (riscv64gc-unknown-linux-gnu)	35s
Cross (aarch64-unknown-linux-gnu)	41s
Windows (stable-i686-msvc)	39s
Web	58s
NetBSD VM	0s
	29m 52s

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