Test for LIMIT case insensitive

[dveeden]

The test was testing for LIMIT and limit but didn't work for Limit etc.

Follow up for #349

@kebhr @mohawk2 what do you think about this?

I think strncasecmp may not be available on Windows, so this might need an ifdef with a Windows specific solution (_strnicmp()).

[mohawk2]

I think you're right that it should be case-insensitive! And my quick googling shows there is indeed a #ifdef needed on Windows.

[kebhr]

I also agree to this change. It will follow the MySQL specification more closely and do not believe that this change will cause a degrade.