Update path of tradefederation projects.

project: platform/tools/tradefederation
  original path: tools/tradefederation
  new path:      tools/tradefederation/core

BUG:36557513
Test: Synced and built on aosp master with success.
- make -j40
- make -j49 javac-check dist DIST_DIR=<local dir> RUN_ERROR_PRONE=true
1 file changed
tree: ccfca09c6993943f6c1b2c0b29623723744bac50
  1. GLOBAL-PREUPLOAD.cfg
  2. default.xml