[lworld] RFR: 8247299: [lworld] Disable UseBiasedLocking by default

[David Simms]

Disabled UseBiasedLocking, and reorganized markWord to serve Valhalla requirements (see also JDK-8247298 for
motivation).

Actual UseBiasedLocking code remains simply to avoid future conflicts. Since static constants have changed and
UseBiasedLocking is deprecated, Valhalla assumes it will be removed, and it is not only disabled "by default", but now
unusable.

Tier1-3 testing clean

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

Commit messages:
 - Remove more biased lock testing
 - extend into hash area for unlocked should_preserve
 - Merge branch 'lworld' into mark_word_without_bias
 - Disable biased locking testing
 - Fix later LoadNode::Value() prototype mark later
 - EnableValhalla guards
 - Init markWord with prototype for klass
 - Don't UseBiasedLocking at all, unconditional changes to markWord
 - Revert to poisioning inline bit for locking slow path, flat is also null free same as klass _layout_helper
 - Oop header minor fix/format
 - ... and 2 more: https://git.openjdk.java.net/valhalla/compare/28fb33d2...4b02f030

Changes: https://git.openjdk.java.net/valhalla/pull/234/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=234&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8247299
  Stats: 759 lines in 42 files changed: 201 ins; 452 del; 106 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/234.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/234/head:pull/234

PR: https://git.openjdk.java.net/valhalla/pull/234