tfs: darwin get secrets

build/tfs/darwin/build.sh

 #!/bin/sh
 set -e
 
+export $VSCODE_MIXIN_PASSWORD = "$1"
+export $AZURE_STORAGE_ACCESS_KEY_2 = "$2"
+export $MOONCAKE_STORAGE_ACCESS_KEY = "$3"
+export $AZURE_DOCUMENTDB_MASTERKEY = "$4"
+
 # set agent specific npm cache
 if [ -z "$AGENT_WORKFOLDER" ]
 then