RFR: 8193559: ugly DO_JAVA_THREADS macro should be replaced [v5]

[Daniel D.Daugherty]

> This is a simple rewrite of what is "Possibly the ugliest for loop the world has seen."
> Thanks to @stefank for the draft proposed fix. Thanks to @fisk for providing this
> piece of history that I'm finally getting around to cleaning up. While this macro has
> been with us for a long time, its time has passed...
> 
> Tested with Mach5 Tier[1-3].

Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:

  kbarrett CR - simplify 'ThreadsList::Iterator::operator!=(Iterator i)'

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4671/files
  - new: https://git.openjdk.java.net/jdk/pull/4671/files/3be5dc72..a8865b8e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4671&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4671&range=03-04

  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4671.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4671/head:pull/4671

PR: https://git.openjdk.java.net/jdk/pull/4671