vendor: update golang.org/x/tools
vendor: update golang.org/x/tools

This picks up https://github.com/golang/tools/commit/ebf631f91, which
allows us to continue growing `sql.y` without incurring the wrath of
`goyacc`'s maximum number of parser states.

vaibhavarora/cockroach,paperstreet/cockroach,maxlang/cockroach,petermattis/cockroach,petermattis/cockroach,petermattis/cockroach,maxlang/cockroach,maxlang/cockroach,paperstreet/cockroach,petermattis/cockroach,petermattis/cockroach,maxlang/cockroach,paperstreet/cockroach,paperstreet/cockroach,glycerine/cockroach,paperstreet/cockroach,glycerine/cockroach,maxlang/cockroach,glycerine/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,petermattis/cockroach,maxlang/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,maxlang/cockroach,petermattis/cockroach,glycerine/cockroach,petermattis/cockroach,glycerine/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,glycerine/cockroach,paperstreet/cockroach,maxlang/cockroach,vaibhavarora/cockroach,glycerine/cockroach,glycerine/cockroach,vaibhavarora/cockroach