[llvm] [flang-rt][test] Skip Driver/safe-trampoline-gnustack.f90 on RISC-V (PR #227851)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

The docs say:

> Since LLVM 23, Flang has a new compiler flag `-fsafe-trampoline`, which is disabled by default and is currently supported on x86-64 and AArch64 targets.

Would it make sense to make this a whitelist instead of a blacklist?

https://github.com/llvm/llvm-project/pull/227851