<rdar://problem/12462048>

LLDB changes argv[0] when debugging a symlink. Now we have the notion of argv0 in the target settings:

target.arg0 (string) = 

There is also the program argument that are separate from the first argument that have existed for a while:

target.run-args (arguments) =

When running "target create <exe>", we will place the untouched "<exe>" into target.arg0 to ensure when we run, we run with what the user typed. This has been added to the ProcessLaunchInfo and all other needed places so we always carry around the:
- resolved executable path
- argv0
- program args

Some systems may not support separating argv0 from the resolved executable path and the ProcessLaunchInfo needs to carry all of this information along so that each platform can make that decision.

llvm-svn: 166137