Store it in the URL cache entry and allow it to be retrieved by 
RetrieveUrlCacheEntryFile and other functions.

wininet: The URL in CommitUrlCacheEntryInternal shouldn't be restricted to MAX_PATH chars in length.

Dynamically allocate it and consolidate cleanup at the end of the function.

wininet: Fix URLCache_LocalFileNameToPathA to return a full path, rather than just the container path.

This was caused by path_len including the nul-terminator and so the rest 
of the string was being added after the nul-terminator, which is 
incorrect. This is fixed by making path_len not include the nul-terminator.

Also fix a few other issues with the function, like not passing a 
correct length into the second call to WideCharToMultiByte, nRequired 
being calculated incorrectly and the string not always being nul-terminated.

Add a test for this function by testing the lpszLocalFileName field 
obtained from RetrieveUrlCacheEntryFileA.

wininet: Use LIST_FOR_EACH_ENTRY in URLCacheContainers_FindContainerW instead of LIST_FOR_EACH and LIST_ENTRY.

wininet: Fix proxy authentication by using the data in lpwhr->pProxyAuthInfo in HTTP_InsertAuthorization instead of lpwhr->pAuthInfo when inserting the Proxy-Authentication header.

Otherwise, the wave-in driver(s) may copy incorrect data to internal structures.