shell32/tests: Copy the PathRemoveBackslashA() and PathAddBackslashW() implementations because shlwapi.dll is missing on Windows 95.

secur32/tests: Dynamically load various APIs and don't link with crypt32.dll to make the test run on Windows 95.

user32/tests: Use GetProcAddress() on ChangeDisplaySettingsExA() because it is missing on Windows 95.

rpcrt4: Don't copy memory from the buffer in NdrConformantStringUnmarshall if we just pointed the memory pointer into the buffer.

(Reported by Dan Kegel.)