[master] RFR: Load Klass* without causing monitor inflation

[Roman Kennke]

Until now, loading the Klass* in Lilliput may cause monitor inflation, because we needed a way to safely load the mark-word in the face of concurrent stack-locking or inflation happening. However, this caused troubles with concurrent GCs, because they may attempt to inflate monitors on from-space objects while traversing the heap for relocation/evacuation. Also, this may be a performance nuisance.
It turns out that we don't have to fully inflate the monitor: we only need a partial inflation, up to where we install the transient INFLATING word to prevent concurrent threads from messing with the mark-word, and then read and return the mark-word safely, and swing back the original real mark word to let other threads continue.

Testing:
 - [x] tier1
 - [x] tier2
 - [ ] tier3
 - [ ] tier4
 - [ ] hotspot_gc

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

Commit messages:
 - Load Klass* without causing monitor inflation

Changes: https://git.openjdk.java.net/lilliput/pull/25/files
 Webrev: https://webrevs.openjdk.java.net/?repo=lilliput&pr=25&range=00
  Stats: 77 lines in 2 files changed: 75 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/lilliput/pull/25.diff
  Fetch: git fetch https://git.openjdk.java.net/lilliput pull/25/head:pull/25

PR: https://git.openjdk.java.net/lilliput/pull/25