Skip helix tests

Author: mmitche

.azure/pipelines/ci.yml

@@ -1,4 +1,4 @@
-#
+ #
 # See https://docs.microsoft.com/en-us/vsts/pipelines/yaml-schema for details on this file.
 #
 
@@ -788,6 +788,7 @@ stages:
       # Helix x64
       - template: jobs/default-build.yml
         parameters:
+          condition: ne(variables['SkipTests'], 'true')
           jobName: Helix_x64
           jobDisplayName: 'Tests: Helix x64'
           agentOs: Windows