RFR: JDK-8302989: Add missing INCLUDE_CDS checks [v2]

[Matthias Baesken]

> The cds only coding in hotspot is usually guarded with the INCLUDE_CDS macro so that it can be removed at compile time in case the correct configure flags are set.
> However at some places INCLUDE_CDS is missing and should be added.
> 
> One question - should (additionally to the UseSharedSpaces code section)  the DumpSharedSpaces code sections be guarded as well with INCLUDE_CDS macros ?

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

  Make SharedSpaces related vars const and false in non CDS mode

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12691/files
  - new: https://git.openjdk.org/jdk/pull/12691/files/6c22a2a7..5dff9614

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12691&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12691&range=00-01

  Stats: 46 lines in 4 files changed: 45 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12691.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12691/head:pull/12691

PR: https://git.openjdk.org/jdk/pull/12691