Extend tjbenchtest so that it tests the dynamic JPEG buffer allocation feature in...

Extend tjbenchtest so that it tests the dynamic JPEG buffer allocation feature in TurboJPEG.  Disable the tiling feature in TJBench whenever dynamic buffer allocation is enabled (because the tiling feature requires a separate buffer for each tile, using it successfully with dynamic buffer allocation would require a separate TurboJPEG compressor instance for each tile, and it's not worth going to that trouble right now.)

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1374 632fc199-4ca6-4c93-a231-07263d6284db