As of 4.3 ResourceHttpRequestHandler delegates to the configured
ContentNegotiationManager, or one created internally, to look up
the media type for are resource.
This commit ensures the internally created ContentNegotiationManager is
correctly injected with the ServletContext through which it can perform
lookups as before.
Also the ServletPathContentNegotiationStrategy now checks the
ServletContext first and then delegates to its parent the
PathContentNegotiationStrategy and not vice versa. This is
consistent with how handleNoMatch (also in the same class) works
and also matches how ResourceHttpRequestHandler worked before 4.3.
Issue: SPR-14368
e38623df87