Downstream test: temporarily exclude istanbul
Downstream test: temporarily exclude istanbul

Closes gh-1542

bcbcarl/esprima,ChromeDevTools/esprima,jquery/esprima,ariya/esprima,ChromeDevTools/esprima,ChromeDevTools/esprima,jquery/esprima,bcbcarl/esprima,jquery/esprima,bcbcarl/esprima,ariya/esprima,ariya/esprima