Switch to a dedicated lintTree hook
Switch to a dedicated lintTree hook

Because postprocessTree runs in series and we need to run linters in
parallel.

ember-cli/ember-cli-qunit,blimmer/ember-cli-qunit,nathanhammond/ember-cli-qunit,nathanhammond/ember-cli-qunit,ember-cli/ember-cli-qunit,zenefits/ember-cli-qunit,zenefits/ember-cli-qunit,blimmer/ember-cli-qunit