RFR: 8256843: [PPC64] runtime/logging/RedefineClasses.java fails with assert: registers not saved on stack

[Martin Doerr]

Method handle logging is broken in fastdebug builds. Problem is that os::current_frame() doesn't return the right frame in fastdebug builds.
Unfortunately, fixing os::current_frame() would break NMT stack traces (runtime/NMT/CheckForProperDetailStackTrace.java).

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Commit messages:
 - 8256843: [PPC64] runtime/logging/RedefineClasses.java fails with assert: registers not saved on stack

Changes: https://git.openjdk.java.net/jdk/pull/1724/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1724&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256843
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1724.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1724/head:pull/1724

PR: https://git.openjdk.java.net/jdk/pull/1724