[compiler-rt] [Sanitizers][ABI] Build ASAN shim for arm64_32 arch (PR #81066)

[via llvm-commits]

thetruestblue wrote:

Are no changes needed in asan_abi cmakes files?

If we want to test shim tests on watch OS the test file checks for archs explicitly:
```
macro(get_bits_for_arch arch bits)
  if (${arch} MATCHES "arm64|x86_64")
    set(${bits} 64)
  else()
    message(FATAL_ERROR "Unknown target architecture: ${arch}")
  endif()
endmacro() 
```

https://github.com/llvm/llvm-project/pull/81066