Convert over to using pipes for the initial LLDB commands in the Driver.

This will avoid having to use a temp file and adding temp file related calls to the public API.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@214536 91177308-0d34-0410-b5e6-96231b3b80d8
Don't hand compute mydir, do it using "TestBase.compute_mydir(__file__)".



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@214575 91177308-0d34-0410-b5e6-96231b3b80d8