Refactor finalization scripts.

Bug: 264308911
Test: run locally
Change-Id: I60fa1e1121fafb617d8508403fae07f0bdf39e66

tools/finalization/cleanup.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+# Brings local repository to a remote head state.
+
+# set -ex
+
+function finalize_revert_local_changes_main() {
+    local top="$(dirname "$0")"/../../../..
+    local m="$top/build/soong/soong_ui.bash --make-mode TARGET_PRODUCT=aosp_arm64 TARGET_BUILD_VARIANT=userdebug"
+
+    # remove the out folder
+    $m clobber
+
+    repo selfupdate
+
+    repo forall -c '\
+        git checkout . ; git revert --abort ; git clean -fdx ;\
+        git checkout @ ; git branch fina-step1 -D ; git reset --hard; \
+        repo start fina-step1 ; git checkout @ ; git b fina-step1 -D ;'
+}
+
+finalize_revert_local_changes_main