[lldb/test] Disable 'TestScriptedProcess.py' on macOS

This is disabling 'TestScriptedProcess.py' on macOS since it fails on
Green Dragon: https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/35974



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>