[clang] [ObjC] Support emission of selector stubs calls instead of objc_msgSend. (PR #183922)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-5` while building `clang` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/38293

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Driver/offload-Xarch.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang --target=x86_64-unknown-linux-gnu -x cuda /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_nvptx64 -O3 -S -nogpulib -nogpuinc -### 2>&1 | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang --target=x86_64-unknown-linux-gnu -x cuda /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_nvptx64 -O3 -S -nogpulib -nogpuinc '-###'
# note: command had no output on stdout or stderr
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# note: command had no output on stdout or stderr
# RUN: at line 2
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -x cuda /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_device -O3 -S -nogpulib -nogpuinc -### 2>&1 | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -x cuda /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_device -O3 -S -nogpulib -nogpuinc '-###'
# note: command had no output on stdout or stderr
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# note: command had no output on stdout or stderr
# RUN: at line 3
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -x hip /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_amdgcn -O3 -S -nogpulib -nogpuinc -### 2>&1 | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -x hip /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c -Xarch_amdgcn -O3 -S -nogpulib -nogpuinc '-###'
# note: command had no output on stdout or stderr
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# note: command had no output on stdout or stderr
# RUN: at line 4
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -fopenmp=libomp -fopenmp-targets=amdgcn-amd-amdhsa -nogpulib -nogpuinc    -Xarch_amdgcn -march=gfx90a -Xarch_amdgcn -O3 -S -### /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c 2>&1  | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -fopenmp=libomp -fopenmp-targets=amdgcn-amd-amdhsa -nogpulib -nogpuinc -Xarch_amdgcn -march=gfx90a -Xarch_amdgcn -O3 -S '-###' /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# note: command had no output on stdout or stderr
# error: command failed with exit status: -6
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck -check-prefix=O3ONCE /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# .---command stderr------------
# | /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c:10:12: error: O3ONCE: expected string not found in input
# | // O3ONCE: "-O3"
# |            ^
# | <stdin>:1:1: note: scanning from here
# | clang version 23.0.0git (https://github.com/llvm/llvm-project.git 6758becb8f19593f5341b2e4d575dbf411ad706e)
# | ^
# | <stdin>:9:200: note: possible intended match here
# | 0. Program arguments: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/clang -fopenmp=libomp -fopenmp-targets=amdgcn-amd-amdhsa -nogpulib -nogpuinc -Xarch_amdgcn -march=gfx90a -Xarch_amdgcn -O3 -S -### /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# |                                                                                                                                                                                                        ^
# | 
# | Input file: <stdin>
# | Check file: /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/clang/test/Driver/offload-Xarch.c
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: clang version 23.0.0git (https://github.com/llvm/llvm-project.git 6758becb8f19593f5341b2e4d575dbf411ad706e) 
# | check:10'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# |             2: Target: arm64-apple-darwin23.6.0 
...

```

</details>

https://github.com/llvm/llvm-project/pull/183922