[clang] [Clang][RISCV] Loose the requirement of cf-protection=return to Zimop (PR #223671)

[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/50084

<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 'LLVM :: ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll' FAILED ********************
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
# .---command stderr------------
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
# |  #0 0x00000001050449a0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f789a0)
# |  #1 0x0000000105041f54 llvm::sys::RunSignalHandlers() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f75f54)
# |  #2 0x000000010504532c SignalHandler(int, __siginfo*, void*) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f7932c)
# |  #3 0x000000019aa53584 (/usr/lib/system/libsystem_platform.dylib+0x18047b584)
# |  #4 0x0000000104b77040 llvm::orc::JITDylib::clear() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100aab040)
# |  #5 0x0000000104b81e14 llvm::orc::ExecutionSession::removeJITDylibs(std::__1::vector<llvm::IntrusiveRefCntPtr<llvm::orc::JITDylib>, std::__1::allocator<llvm::IntrusiveRefCntPtr<llvm::orc::JITDylib>>>) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100ab5e14)
# |  #6 0x0000000104b81bac llvm::orc::ExecutionSession::endSession() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100ab5bac)
# |  #7 0x0000000104c19bcc llvm::orc::LLLazyJIT::~LLLazyJIT() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100b4dbcc)
# |  #8 0x0000000104c19cc8 llvm::orc::LLLazyJIT::~LLLazyJIT() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100b4dcc8)
# |  #9 0x00000001040d4564 runOrcJIT(char const*) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100008564)
# | #10 0x00000001040cfa70 main (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100003a70)
# | #11 0x000000019a697154
# `-----------------------------
# error: command failed with exit status: -11
# executed command: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
# `-----------------------------
# error: command failed with exit status: 2

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/223671