Protect against NPE in Tiles 3 Views

Change the org.apache.tiles.request.servlet.ServletRequest created
in TileView.checkResource to include the HttpServletRequest. This
is required when using a TilesConfigurer with useMutableTilesContainer
set to true. Without a HttpServletRequest the getRequestScope() method
will always return null causing exceptions in the CachingTilesContainer
class.

Unfortunately the checkResource method does not provide access to the
HttpServletRequest so it must be obtained via the RequestContextHolder
thread-local.

Issue: SPR-10223