Fix variable names for instance variable blocks (#3269)
Fix variable names for instance variable blocks (#3269)


playi/pxt,switch-education/pxt,Microsoft/pxt,switchinnovations/pxt,switch-education/pxt,playi/pxt,switch-education/pxt,playi/pxt,playi/pxt,Microsoft/pxt,Microsoft/pxt,Microsoft/pxt,switch-education/pxt,Microsoft/pxt,switchinnovations/pxt,switch-education/pxt,switchinnovations/pxt,switchinnovations/pxt