This PR removes `RuntimeType`/`NullableClass` and related methods, as they are no longer used (after recent cleanup to `ArrayCreation`).
------------- Commit messages: - Merge branch 'bworld' into drop_runtime_type - Drop RuntimeType/NullableClass - Address review comments - Merge branch 'bworld' into strict_array_trans - Add regression test - Initial push Changes: https://git.openjdk.org/valhalla/pull/1878/files Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1878&range=00 Stats: 250 lines in 7 files changed: 0 ins; 248 del; 2 mod Patch: https://git.openjdk.org/valhalla/pull/1878.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1878/head:pull/1878 PR: https://git.openjdk.org/valhalla/pull/1878
