[OpenMP][test]Flip bit-fields in 'struct flags' for big-endian in test cases (#79895)

This patch flips bit-fields in `struct flags` for big-endian in test
cases to be consistent with the definition of the structure in libomp
`kmp.h`.

GitOrigin-RevId: 7a9b0e4acb3b5ee15f8eb138aad937cfa4763fb8
4 files changed