[llvm] [libc] add uefi fullbuild to workflows (PR #131376)

[Tristan Ross via llvm-commits]

RossComputerGuy wrote:

Tests fail due to:
```
error: backend data layout 'e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128' does not match expected target description 'e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128'
```

#120632 fixes it

https://github.com/llvm/llvm-project/pull/131376