[llvm] [flang] [flang-rt] Subscript overrun could occur in namelists during a READ command. (PR #176959)

[Tarun Prabhu via llvm-commits]

tarunprabhu wrote:

> There was not an opened issue. This was my first fix and I never opened one. It was identified when we ran an internal cray test against flang. If I need to (or you'd just prefer), I will open one. The PR will end up being a description of a core/hanging and the test associated with this PR: [llvm/llvm-test-suite#361](https://github.com/llvm/llvm-test-suite/pull/361).
> 
> Please let me know how I should proceed and I'll be happy to. Thank you for looking.

You don't strictly, but the title of the PR said "could occur", so I was wondering if there was a test that actually triggered it that others could use to reproduce. Might be worth opening an issue.

https://github.com/llvm/llvm-project/pull/176959