[llvm] [Flang-RT][test] Add flang-rt-mod dependency (PR #201297)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

The buildbot complaining could be an infra issue. I put up https://github.com/llvm/llvm-zorg/pull/861 which is a general improvement to that bot and may resolve the issue.

https://github.com/llvm/llvm-project/pull/201297