Improve the way LLDB escapes arguments before passing them to the shell

Teach LLDB that different shells have different characters they are sensitive to, and use that knowledge to do shell-aware escaping

This helps solve a class of problems on OS X where LLDB would try to launch via sh, and run into problems if the command line being passed to the inferior contained such special markers (hint: the shell would error out and we'd fail to launch)
This makes those launch scenarios work transparently via shell expansion

Slightly improve the error message when this kind of failure occurs to at least suggest that the user try going through 'process launch' directly

Fixes rdar://problem/22749408

llvm-svn: 265357