RFR: 8263017: Read barriers are missing in nmethod printing code

[Vladimir Ivanov]

OOP accesses from nmethod printing code miss read barriers. 
It causes sporadic crashes when the code stumbles upon a stale OOP.

When `nmethod::print_nmethod` is invoked, the corresponding nmethod is already installed in the code cache and there was a safepoint check in between (see `ThreadToNativeFromVM` usage in `CompileBroker::invoke_compiler_on_method`).
 
The fix adds missing read barriers in `oop_Relocation::oop_value()` and introduces `oop_Relocation::raw_oop_value()` for cases when read barriers aren't needed.

Along the way, there are some cleanups applied (e.g, `nmethod::print_[oops|metadata]` is superseded by `nmethod::print_recorded_[oops|metadata]`).

Testing:
- [x] failing test w/ `-XX:+UseZGC` `-XX:ZCollectionInterval=0.01` `-XX:ZFragmentationLimit=0`
- [x] hs-tier1 - hs-tier4

Thanks!

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Commit messages:
 - Fix nmethod print code

Changes: https://git.openjdk.java.net/jdk/pull/2919/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2919&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263017
  Stats: 117 lines in 8 files changed: 28 ins; 71 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2919.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2919/head:pull/2919

PR: https://git.openjdk.java.net/jdk/pull/2919