Fixing perfnow issue (#1150)
Fixing perfnow issue (#1150)

* Fixing perfnow Issue
switchinnovations/pxt,switch-education/pxt,Microsoft/pxt,switch-education/pxt,playi/pxt,switchinnovations/pxt,playi/pxt,switchinnovations/pxt,playi/pxt,switch-education/pxt,switch-education/pxt,switch-education/pxt,playi/pxt,switchinnovations/pxt,Microsoft/pxt,Microsoft/pxt,Microsoft/pxt,Microsoft/pxt