[LLDB] Mark some xfails for arm-linux

This patch marks following tests as xfail for arm-linux target.

lldb/test/API/functionalities/load_using_paths/TestLoadUsingPaths.py
lldb/test/API/python_api/thread/TestThreadAPI.py
lldb/test/Shell/Recognizer/assert.test

Bugs have been filed for all of them for the corresponding failing
component.