[Bug target/120858] __builtin_rev_crc64_data64 poorly optimised when computing crc32

[sh1.gccbug at tikouka dot nz via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120858

--- Comment #1 from Simon H. <sh1.gccbug at tikouka dot nz> ---
Slightly more 'valid' test, removing possible doubt about input endianness:
https://godbolt.org/z/e63f7KGbj