Add fetch source to upload-java for tag-based uploads. (#884)

JAVA-5590
---------

Co-authored-by: Kevin Albertson <kevin.albertson@10gen.com>

Author: vbabanin

.evergreen/config.yml

@@ -571,6 +571,7 @@ tasks:
     - variant: macos
       name: build-and-test-and-upload
   commands:
+    - func: "fetch source" # To set `tag_upload_location` expansion.
     - command: shell.exec
       params:
         script: mkdir all