Change metalava repo to use DIST_DIR
Change metalava repo to use DIST_DIR

We were assuming that the DIST_DIR and CHECKOUT_ROOT/out/dist were the same. In CI, DIST_DIR is set separately, so METALAVA_REPO was pointing to the incorrect location.

Bug: 258477743
Test: presubmit
Change-Id: Ia93703741de3dd1c22c12bf70d650cf3dcf5979f

androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx