Revert "8366841: [lworld] Objects.equals without identity comparison". (Almost all) Removing the condition on --enable-preview. Correct the .equals method in test SimplValueGraphs.SimpleValue.
------------- Commit messages: - Restore the mainline implementation of Objects.equal Changes: https://git.openjdk.org/valhalla/pull/1836/files Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1836&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8373930 Stats: 10 lines in 2 files changed: 0 ins; 6 del; 4 mod Patch: https://git.openjdk.org/valhalla/pull/1836.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1836/head:pull/1836 PR: https://git.openjdk.org/valhalla/pull/1836
