use tmpfile to make cuda backend safer #3426

Job	Run time
macOS / release / homebrew-clang	5m 7s
Windows / release / msvc	24m 25s
macOS / debug / homebrew-clang	4m 58s
Windows / release / clang-cl	22m 19s
macOS / release / system-clang	5m 20s
Windows / release / llvm	19m 32s
macOS / debug / system-clang	4m 59s
Windows / debug / msvc	18m 29s
Windows / debug / clang-cl	21m 13s
Windows / debug / llvm	22m 11s
	2h 28m 33s

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