[compiler-rt] [compiler-rt] Fix tests of __aeabi_(idivmod|uidivmod|uldivmod) to support big endian (PR #126277)

[Simon Tatham via llvm-commits]

https://github.com/statham-arm approved this pull request.

Ah, now I look at the tests of 32-bit division, I understand!

Yes, this version of the patch makes much more sense, because now I see that the test code is hacking around lack of support for `__value_in_regs` by pretending that `__aeabi_idivmod` returns a `uint64_t`, and then breaks it up into quotient and remainder halves, which needs to be done opposite ways round depending on the endianness of that integer.

I've pressed the approve button, but you might consider adding a comment to explain that, since it might very well not be obvious to the next person reading this code?

https://github.com/llvm/llvm-project/pull/126277