RFR: 7904039: jcstress: Rework Dekker tests to include reference types [v2]

[Aleksey Shipilev]

> [JDK-8351997](https://bugs.openjdk.org/browse/JDK-8351997) shows there is a gap in testing: we only verify Dekker-style scenarios over primitive volatiles. We need to extend this to reference types.
> 
> There is a larger amendment to include reference types in seqcst-generator tests.

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

  Fix the test name

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Changes:
  - all: https://git.openjdk.org/jcstress/pull/169/files
  - new: https://git.openjdk.org/jcstress/pull/169/files/7c031ba8..90ed392b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jcstress&pr=169&range=01
 - incr: https://webrevs.openjdk.org/?repo=jcstress&pr=169&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jcstress/pull/169.diff
  Fetch: git fetch https://git.openjdk.org/jcstress.git pull/169/head:pull/169

PR: https://git.openjdk.org/jcstress/pull/169