RFR: 8332105: Exploded JDK does not include CDS [v2]

[Thomas Stuefe]

> An exploded JDK cannot be used with either -Xshare:on or -Xshare:auto. That causes tests like runtime/CompressedOops/CompressedCPUSpecificClassSpaceReservation.java to fail when running on an exploded JDK.
> 
> Since an exploded JDK cannot use CDS, we should - for tests - treat it as if CDS had not been included.
> 
> 
> ----
> 
> Note that I was torn between two ways to fix this:
> 
> - either this fix, which is rather simple and automatically updates the "vm.cds" `@requires` property
> - or to expose "exploded-ness" as a boolean property via `WhiteBox` and `VMProps`(`jdk.exploded`). See this draft PR: https://github.com/openjdk/jdk/pull/19178 . 
> 
> The latter is cleaner and clearer, conveying the message of exploded-ness without muddling it with the CDS aspect. But OTOH the complexity may not be required. 
> 
> I can go either way, though I have a slight preference for this PR, which is why I posted it.

Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8332105-Exploded-JDK-should-count-as-if-CDS-had-not-been-included-in-the-build
 - JDK-8332105-Exploded-JDK-should-count-as-if-CDS-had-not-been-included-in-the-build

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19188/files
  - new: https://git.openjdk.org/jdk/pull/19188/files/179d00b3..b9d17dce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19188&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19188&range=00-01

  Stats: 135873 lines in 2635 files changed: 90868 ins; 31523 del; 13482 mod
  Patch: https://git.openjdk.org/jdk/pull/19188.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19188/head:pull/19188

PR: https://git.openjdk.org/jdk/pull/19188