RFR: 8262424: Change multiple get_java_xxx() functions in thread.cpp into one function [v2]

[Harold Seigel]

> Please review this small fix to change the multiple get_java_xxx() functions in thread.cpp into a single function.
> 
> The fix was tested with Mach5 tiers 1 and 2 on Linux, Mac OS, and Windows, and tiers 3-5 on Linux x64.
> 
> Thanks, Harold

Harold Seigel has updated the pull request incrementally with one additional commit since the last revision:

  make global buffers static

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2750/files
  - new: https://git.openjdk.java.net/jdk/pull/2750/files/2d8f10cc..9af8e615

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2750&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2750&range=00-01

  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2750.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2750/head:pull/2750

PR: https://git.openjdk.java.net/jdk/pull/2750