[llvm] [NFC] Remove deprecated Argument::getParamAlignment() declaration (PR #169911)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `llvm` at step 6 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/42608

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

```
Step 6 (test-build-unified-tree-check-flang) failure: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
...
PASS: Flang :: Semantics/typeinfo03.f90 (4021 of 4031)
PASS: Flang :: Transforms/debug-dwarf-version.fir (4022 of 4031)
PASS: Flang :: Driver/fopenmp.f90 (4023 of 4031)
PASS: Flang :: Transforms/DoConcurrent/use_loop_bounds_in_body.f90 (4024 of 4031)
PASS: Flang :: Transforms/tbaa3.fir (4025 of 4031)
PASS: Flang :: Transforms/OpenACC/acc-implicit-data-fortran.F90 (4026 of 4031)
PASS: Flang :: Lower/OpenMP/rtl-flags.f90 (4027 of 4031)
PASS: Flang :: Driver/omp-driver-offload.f90 (4028 of 4031)
PASS: Flang :: Driver/linker-options.f90 (4029 of 4031)
PASS: Flang :: Intrinsics/math-codegen.fir (4030 of 4031)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=2153.906645

```

</details>

https://github.com/llvm/llvm-project/pull/169911