[llvm] [flang] Don't associate pointers with zero sized storage targets (PR #155867)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-sve-vls` running on `linaro-g3-01` while building `flang-rt` at step 14 "test-suite".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/143/builds/10381

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 14 (test-suite) failure: test (failure)
******************** TEST 'test-suite :: Fortran/gfortran/regression/gfortran-regression-execute-regression__pointer_init_8_f90.test' FAILED ********************

/home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/tools/timeit-target --timeout 7200 --limit-core 0 --limit-cpu 7200 --limit-file-size 209715200 --limit-rss-size 838860800 --redirect-input /dev/null --chdir /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/gfortran-regression-execute-regression__pointer_init_8_f90.wd --summary /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/Output/gfortran-regression-execute-regression__pointer_init_8_f90.test.time /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/gfortran-regression-execute-regression__pointer_init_8_f90

+ /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/tools/timeit-target --timeout 7200 --limit-core 0 --limit-cpu 7200 --limit-file-size 209715200 --limit-rss-size 838860800 --redirect-input /dev/null --chdir /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/gfortran-regression-execute-regression__pointer_init_8_f90.wd --summary /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/Output/gfortran-regression-execute-regression__pointer_init_8_f90.test.time /home/tcwg-buildbot/worker/clang-aarch64-sve-vls/test/sandbox/build/Fortran/gfortran/regression/gfortran-regression-execute-regression__pointer_init_8_f90
Fortran STOP: code 1


********************


```

</details>

https://github.com/llvm/llvm-project/pull/155867