RFR: 8261905: Move implementation of OopStorage num_dead related functions [v2]

[Kim Barrett]

> Please review this trivial change which just moves several functions to a
> different location in the same file.  The old location is in the middle of
> some unrelated functionality.
> 
> Testing:
> mach5 tier1

Kim Barrett 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 move_num_dead
 - move num_dead functions

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2608/files
  - new: https://git.openjdk.java.net/jdk/pull/2608/files/baa9f5d2..578009f4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2608&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2608&range=00-01

  Stats: 947 lines in 49 files changed: 661 ins; 155 del; 131 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2608.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2608/head:pull/2608

PR: https://git.openjdk.java.net/jdk/pull/2608