Fixes more incorrect #ifs for SJ/LJ exceptions

Replaces several `#if __arm__` with `#if __USING_SJLJ_EXCEPTIONS__`.


git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@208352 91177308-0d34-0410-b5e6-96231b3b80d8