When reapplying JDK-8252505 to jdk/jdk, I stumbled upon the bad merge.

This was the original changeset:
  https://github.com/openjdk/jdk16/commit/ad456787

This was the merge:
https://github.com/openjdk/jdk/commit/555641ede5e234c936fca98436ef6aeace2351fc

Note that not all blocks were removed from compilerOracle.