WinSxS DLLs are found via find_actctx_dll(). When activation contexts are inactive, GetModuleHandle() shouldn't find WinSxS DLLs with the same base name of a normal DLL.
-- v3: ntdll: Exclude SxS DLLs when finding a DLL with its base name and no activation contexts. kernel32/tests: Add more GetModuleHandle() tests for WinSxS.