Add D request handler to GDBRemoteCommunicationServer in order to support detach from inferior.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@223901 91177308-0d34-0410-b5e6-96231b3b80d8
Skip TestExprPathSynthetic test on FreeBSD, Linux & Windows.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@223905 91177308-0d34-0410-b5e6-96231b3b80d8