[clang] [Hexagon] Add scs multilib for -fsanitize=shadow-call-stack (PR #208833)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-x86_64-debian-dylib` running on `gribozavr4` while building `clang` at step 6 "test-build-unified-tree-check-clang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/60/builds/4238

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

```
Step 6 (test-build-unified-tree-check-clang) failure: test (failure)
******************** TEST 'Clang :: CodeGen/SystemZ/zos-check-lanuage.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 4
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x c - < /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c | grep -v DIFile > /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x c -
# executed command: grep -v DIFile
# RUN: at line 5
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-ast -o /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-ast -o /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c
# RUN: at line 6
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x ast - < /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast | grep -v DIFile > /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x ast -
# executed command: grep -v DIFile
# RUN: at line 7
diff /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# executed command: diff /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# RUN: at line 10
/b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck --check-prefix CHECK-C /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c < /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll
# executed command: /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck --check-prefix CHECK-C /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c
# RUN: at line 14
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x c++ - < /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c | grep -v DIFile > /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x c++ -
# executed command: grep -v DIFile
# RUN: at line 15
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-ast -o /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast -x c++ /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-ast -o /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast -x c++ /b/1/llvm-x86_64-debian-dylib/llvm-project/clang/test/CodeGen/SystemZ/zos-check-lanuage.c
# RUN: at line 16
env SDKROOT="/" /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x ast - < /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp.ast | grep -v DIFile > /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# executed command: env SDKROOT=/ /b/1/llvm-x86_64-debian-dylib/build/bin/clang -target s390x-none-zos -emit-llvm -S -o - -x ast -
# executed command: grep -v DIFile
# RUN: at line 17
diff /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# executed command: diff /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# .---command stdout------------
# | *** /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp1.ll
# | --- /b/1/llvm-x86_64-debian-dylib/build/tools/clang/test/CodeGen/SystemZ/Output/zos-check-lanuage.c.tmp2.ll
# | ***************
# | *** 21,27 ****
# |   !2 = !{i32 2, !"zos_product_patchlevel", i32 0}
# |   !3 = !{i32 1, !"zos_product_id", !"clang"}
# |   !4 = !{i32 1, !"zos_cu_language", !"C++"}
# | ! !5 = !{i32 7, !"zos_translation_time", i32 1784542937}
# |   !6 = !{i32 1, !"zos_le_char_mode", !"ascii"}
# |   !7 = !{i32 7, !"frame-pointer", i32 2}
# |   !8 = !{!"clang version 23.0.0git (https://github.com/llvm/llvm-project.git 3f12bb1f25b88e338679c42ccaea11fe204a0e1c)"}
# | --- 21,27 ----
# |   !2 = !{i32 2, !"zos_product_patchlevel", i32 0}
...

```

</details>

https://github.com/llvm/llvm-project/pull/208833