RFR: 8260473: [vector] ZGC: VectorReshape test produces incorrect results with ZGC enabled [v5]

[王超]

> https://bugs.openjdk.java.net/browse/JDK-8260473
> 
> Function "PhaseVector::expand_vunbox_node" creates a LoadNode, but forgets to make the LoadNode to pass gc barriers.
> 
> 
> Testing: all Vector API related tests have passed.

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

  Several modification:
  
  1, require Z gc
  2, Use testng Assert
  3, Rename the test
  4, get the right INVOC_COUNT

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2253/files
  - new: https://git.openjdk.java.net/jdk/pull/2253/files/d52fd4c4..da06b0aa

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2253&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2253&range=03-04

  Stats: 293 lines in 2 files changed: 162 ins; 131 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2253.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2253/head:pull/2253

PR: https://git.openjdk.java.net/jdk/pull/2253