moved GLOBAL, SESSION, and VARIABLES to non_reserved_keyword

[slanning]

This also fixes an omission from b61debd
to remove the extra STATUS left in reserved_keyword .

I wasn't sure about GLOBAL and SESSION from my previous commit e5655b8 ,
so I left them for now but possibly they also should be in non_reserved_keyword.

(This is a second attempt at my botched PR #3577 ...)

[bbeaudreault]

In terms of your question around GLOBAL and SESSION, the general rule of thumb is to try non_reserved_keyword first. If it causes conflicts, put it in reserved_keyword. This is safe because we quote all the keywords anyway.

So if you're wondering I'd try moving GLOBAL/SESSION to non_reserved_keyword, and see if make returns any shift/reduce or reduce/reduce conflicts. If not, great! If so, just leave as is.

[slanning]

Thanks for the feedback. I'll try that tomorrow. (I did have a shift-reduce conflict when making the original change, and it's quite possible that putting it in reserved_keyword is just a relic of an attempt at resolving that...)

[sougou]

LGTM