RFR: 8272165: Consolidate mark_must_be_preserved() variants [v2]

[Roman Kennke]

> We have markWord::mark_must_be_preserved() and markWord::mark_must_be_preserved_for_promotion_failure(). We used to have slightly different implementations when we had BiasedLocking, but now they are identical and used for identical purposes too. Let's remove what we don't need.
> 
> Testing:
>  - [x] hotspot_gc
>  - [x] tier1
>  - [x] tier2

Roman Kennke has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into JDK-8272165
 - 8272165: Consolidate mark_must_be_preserved() variants

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5057/files
  - new: https://git.openjdk.java.net/jdk/pull/5057/files/ebeace12..e66ddc7c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5057&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5057&range=00-01

  Stats: 8049 lines in 220 files changed: 6586 ins; 688 del; 775 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5057.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5057/head:pull/5057

PR: https://git.openjdk.java.net/jdk/pull/5057