[compiler-rt] [builtins] Guard the divtc3_test.c test with CRT_HAS_TF_MODE (PR #71876)

[Amara Emerson via llvm-commits]

aemerson wrote:

I think it's something to do with the clang version on the bot being older by a few years. I'm not entirely sure, can this go in anyway since we need to get it back to green?

https://github.com/llvm/llvm-project/pull/71876