[lldb] Fix TestGlobalModuleCache.py for remote debugging (llvm#111483)

`SBDebugger().Create()` returns a debugger with only the host platform
in its platform list. If the test suite is running for a remote
platform, it should be explicitly added and selected in the new debugger
created within the test, otherwise, the test will fail because the host
platform may not be able to launch the built binary.

Author: igorkudrin

lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py

@@ -111,6 +111,7 @@ def do_test(self, one_target, one_debugger):
         else:
             if one_target:
                 new_debugger = lldb.SBDebugger().Create()
+                new_debugger.SetSelectedPlatform(lldb.selected_platform)
                 new_debugger.SetAsync(False)
                 self.old_debugger = self.dbg
                 self.dbg = new_debugger