fallback: alloca alignments update #3331

Job	Run time
macOS / Release / homebrew-clang	6m 46s
Ubuntu / Release / gcc	25m 10s
macOS / Debug / homebrew-clang	6m 6s
Ubuntu / Debug / gcc	18m 25s
macOS / Release / system-clang	6m 16s
Ubuntu / Release / clang	17m 39s
macOS / Debug / system-clang	6m 9s
Ubuntu / Debug / clang	13m 32s
Windows / Release / cl	29m 17s
Windows / Release / clang	34m 2s
Windows / Release / clang-cl	23m 22s
Windows / Debug / cl	24m 31s
Windows / Debug / clang	24m 43s
Windows / Debug / clang-cl	23m 39s
	4h 19m 37s

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