[libunwind] [libunwind][test] unsupport a test in aarch64 for aarch64 has corss toolchain build (PR #156383)

[Wu Yingcong via cfe-commits]

yingcong-wu wrote:

Add arm as armv7 also have the cross-toolchain build(https://lab.llvm.org/buildbot/#/builders/38/builds/5190).

https://github.com/llvm/llvm-project/pull/156383