RFR: 8266618: Remove broken -XX:-OptoRemoveUseless

[Tobias Hartmann]

Similar to [JDK-8266542](https://bugs.openjdk.java.net/browse/JDK-8266542), simply running `java -XX:-OptoRemoveUseles`s already crashes the VM. I propose to remove this debug flag.

Thanks,
Tobias

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Commit messages:
 - 8266618: Remove broken -XX:-OptoRemoveUseless

Changes: https://git.openjdk.java.net/jdk/pull/3896/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3896&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266618
  Stats: 8 lines in 3 files changed: 0 ins; 6 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3896.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3896/head:pull/3896

PR: https://git.openjdk.java.net/jdk/pull/3896