[lldb] Make TestPlatformMacOSX compatible with stable/20211026

Some of the GDB remote client modules had been moved upstream.

Author: JDevlieghere

lldb/test/API/functionalities/gdb_remote_client/TestPlatformMacOSX.py

@@ -1,8 +1,7 @@
 import lldb
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test.decorators import *
-from lldbsuite.test.gdbclientutils import *
-from lldbsuite.test.lldbgdbclient import GDBRemoteTestBase
+from gdbclientutils import *
 
 
 class TestPlatformMacOSX(GDBRemoteTestBase):