RFR: 8250888: nsk/jvmti/scenarios/general_functions/GF08/gf08t001/TestDriver.java fails [v2]

[Guoxiong Li]

> Hi all,
> 
> `TestDriver.java` used `sun.hotspot.WhiteBox.getBooleanVMFlag("Use*GC")` which could return null.
> This patch uses `sun.hotspot.gc.GC` instead of `sun.hotspot.WhiteBox` to avoid the NullPointerException.
> Thank you for taking the time to review.
> 
> Best Regards.

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

  Use `GC.isSelected` instead of `GC.isSupported`

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1319/files
  - new: https://git.openjdk.java.net/jdk/pull/1319/files/13d243a4..97ad6ca6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1319&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1319&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1319.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1319/head:pull/1319

PR: https://git.openjdk.java.net/jdk/pull/1319