Fix _bzhi_u64() issue #817

Job	Run time
linux_gcc (ubuntu-latest, Debug)	4m 53s
linux_128bit	11m 44s
linux_gcc (ubuntu-latest, Release)	1m 43s
linux_clang (ubuntu-latest, Debug)	6m 15s
linux_clang (ubuntu-latest, Release)	3m 19s
linux_clang_mpopcnt (ubuntu-latest, Debug)	6m 7s
linux_gcc_mpopcnt (ubuntu-latest, Debug)	4m 37s
linux_gcc_sanitizers	3m 10s
linux_gcc_mpopcnt (ubuntu-latest, Release)	1m 16s
linux_clang_mpopcnt (ubuntu-latest, Release)	2m 49s
linux_gcc_valgrind	1m 38s
macos_clang (macos-latest, Debug)	7m 35s
windows_mingw64 (windows-latest, Debug)	9m 36s
macos_clang (macos-latest, Release)	2m 56s
windows_mingw64 (windows-latest, Release)	3m 58s
windows_msvc2022	2m 18s
windows_msvc2022_POPCNT	2m 37s
	1h 16m 31s

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