RFR: 8267914: Remove DeferredObjectToKlass workaround

[Stefan Karlsson]

In JKD-8229839 we fixed a circular dependency problem between oop.inline.hpp and markWord.inline.hpp.  When JDK-8267464: 
'Circular-dependency resilient inline headers' gets integrated, this workaround isn't needed anymore.

-------------

Commit messages:
 - 8267914: Remove DeferredObjectToKlass workaround

Changes: https://git.openjdk.java.net/jdk/pull/4242/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4242&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267914
  Stats: 31 lines in 3 files changed: 1 ins; 22 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4242.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4242/head:pull/4242

PR: https://git.openjdk.java.net/jdk/pull/4242