RFR: 8259475: Fix bad merge in compilerOracle

[Aleksey Shipilev]

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.

Attention @JesperIRL.

Additional testing:
  - [x] Patch from JDK-8252505 applies now
  - [x] No refrerences to "blackhole" or "Blackhole" in `src/hotspot` now

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Commit messages:
 - 8259475: Fix bad merge in compilerOracle

Changes: https://git.openjdk.java.net/jdk/pull/2002/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2002&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259475
  Stats: 17 lines in 2 files changed: 0 ins; 17 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2002.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2002/head:pull/2002

PR: https://git.openjdk.java.net/jdk/pull/2002