[flang] Fix source allocation to explicit length after deferred length object (#87785)

Flang supports source allocation to allocatable or pointers with a non
deferred length that do not match the source length. This documented at:
https://github.com/llvm/llvm-project/blob/9708d0900311503aa4685d6810d8caf0412e15d7/flang/docs/Extensions.md?plain=1#L312

The current lowering code was bugged when such explicit length allocate
object appeared after a deferred length object in the source allocation
list:

Since "lenParams" had been computed when generating allocation of the
deferred length object, the call to genSetDeferredLengthParameters was
not a no-op on when lowering the explicit length allocation, and the
explicit length was overridden with the source length.

The output of the program added in test was:

```
ZZheZZ
ZZhelloZZ
ZZhelloZZ
```

Instead of:

```
ZZheZZ
ZZhelloZZ
ZZhello  ZZ
```

Skip genSetDeferredLengthParameters when the allocate object has non
deferred length.

GitOrigin-RevId: 6a7da2e30dc38ba92875bfe1da5520c950bab1e3
2 files changed
tree: de751a5e1cc23fa59cb96c113d9b1da998248323
  1. cmake/
  2. docs/
  3. examples/
  4. include/
  5. lib/
  6. module/
  7. runtime/
  8. test/
  9. tools/
  10. unittests/
  11. .clang-format
  12. .clang-tidy
  13. .drone.star
  14. .gitignore
  15. CMakeLists.txt
  16. CODE_OWNERS.TXT
  17. LICENSE.TXT
  18. README.md
README.md

Flang

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