RFR: 8256050: JVM crashes with -XX:+PrintDeoptimizationDetails

[Vladimir Ivanov]

-XX:+PrintDeoptimizationDetails triggers intermittent crashes. I spotted 2 independent problems which the patch addresses:
  * `markWord::print_on` doesn't handle displaced header case well (the pointer stored in the header may be stale);
  * `InstanceKlass::oop_print_value_on` dumps some specific details about `MemberName`, but the code assumes the instance is fully initialized. It's necessarily the case: for example, deoptimization can happen when `MemberName` constructor is being executed.  

Testing:
- [x] manually verified that the crashes go away -XX:+PrintDeoptimizationDetails
- [x] hs-precheckin-comp,hs-tier1,hs-tier2

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Commit messages:
 - Fix PrintDeoptimizationDetails

Changes: https://git.openjdk.java.net/jdk/pull/1124/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1124&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256050
  Stats: 30 lines in 7 files changed: 15 ins; 0 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1124.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1124/head:pull/1124

PR: https://git.openjdk.java.net/jdk/pull/1124