RFR: 8254773: Remove unimplemented ciReplay::is_loaded(Klass* klass)

[Aleksey Shipilev]

Both overloads for Klass* and Method* were added by JDK-6830717. But Klass* overload was never implemented:
http://hg.openjdk.java.net/hsx/hsx25/hotspot/rev/bd7a7ce2e264#l32.934

Testing:
 - [x] Linux x86_64 build

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Commit messages:
 - 8254773: Remove unimplemented ciReplay::is_loaded(Klass* klass)

Changes: https://git.openjdk.java.net/jdk/pull/658/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=658&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254773
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/658.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/658/head:pull/658

PR: https://git.openjdk.java.net/jdk/pull/658