Annote expected failures on FreeBSD due to pr14540

PR title updated to indicate that FreeBSD is also affected: Backtrace
command does not display c++ member function names on Linux or FreeBSD


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@187127 91177308-0d34-0410-b5e6-96231b3b80d8