RFR: 8280437: Move G1BufferNodeList to gc/shared [v2]

[Kim Barrett]

> Please review this simple (trivial?) change, renaming G1BufferNodeList to
> BufferNodeList and moving its files from gc/g1 to gc/shared.
> 
> 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 rename-bnl
 - rename G1BufferNodeList

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7183/files
  - new: https://git.openjdk.java.net/jdk/pull/7183/files/3761c3e4..288acaf3

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7183&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7183&range=00-01

  Stats: 774 lines in 78 files changed: 498 ins; 112 del; 164 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7183.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7183/head:pull/7183

PR: https://git.openjdk.java.net/jdk/pull/7183