[Ravenwood] Cleaner sharding

- Use a string constant to remove the duplicate
- Fix the API dump file. Sharded output wasn't all correct.
- Increase the number of shards to 10.
  (Though it doesn't seem to improve the speed)

Bug: 313930116
Test: Ensure ./ravenwood/scripts/ravenwood-stats-collector.sh uses "_all"

Test: m ravenwood-runtime # ensure there are 10 shards

Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Flag: EXEMPT host side test change only
Change-Id: Id65e427261acaa3a910077d2635e746253ab92f7