[llvm] [flang][runtime] Fix child input bugs under NAMELIST (PR #151571)

[Daniel Chen via llvm-commits]

DanielCChen wrote:

Sorry. I just came back from vacation.
The full test case is still failing due to XLF extension. I will still need to investigate more. 
At the same time, this PR is good to go as it fixed the original SIGABRT.

https://github.com/llvm/llvm-project/pull/151571