RFR: JDK-8302043: [ AIX ] Safefetch fails for bad_addressN and bad_address32 [v2]

[Varada M]

> On AIX, reading from lower range addresses like 5120(5K) does not cause a segmentation fault, though writing to them does. Hence the safefetch tests don't run as expected on AIX. This is solved by setting bad_addressN and bad_address32 to -1 for AIX. 
> These tests under NMTGtests.java also passes :
> gtest/NMTGtests.java#nmt-detail
> gtest/NMTGtests.java#nmt-summary
> gtest/NMTGtests.java#nmt-off
> 
> Reported issue: [JDK-8302043](https://bugs.openjdk.org/browse/JDK-8302043)

Varada M has updated the pull request incrementally with two additional commits since the last revision:

 - Updated the segfault address for AIX
 - Updated the segfault address for AIX

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12468/files
  - new: https://git.openjdk.org/jdk/pull/12468/files/1e334e78..46c9c0ab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12468&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12468&range=00-01

  Stats: 7 lines in 2 files changed: 3 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/12468.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12468/head:pull/12468

PR: https://git.openjdk.org/jdk/pull/12468