RFR: 8298470: Short cut java.lang.Object super class loading

[Coleen Phillimore]

While investigating another bug, I found doing this simple optimization saves taking out a SystemDictionary_lock, adding and removing a placeholder and some Symbol refcounting.
Tested with tier1-4.

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Commit messages:
 - 8298470: Short cut java.lang.Object super class loading

Changes: https://git.openjdk.org/jdk/pull/11711/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11711&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298470
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11711.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11711/head:pull/11711

PR: https://git.openjdk.org/jdk/pull/11711