RFR: 8253098: Archived full module graph should be disabled if CDS heap cannot be mapped

[Ioi Lam]

Please review this simple fix -- `MetaspaceShared::use_full_module_graph()` depends on the CDS heap. It should be
disabled if the CDS heap cannot be mapped.

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Commit messages:
 - 8253098: Disable archived module graph if CDS heap cannot be mapped

Changes: https://git.openjdk.java.net/jdk/pull/158/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=158&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253098
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/158.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/158/head:pull/158

PR: https://git.openjdk.java.net/jdk/pull/158