[crac] RFR: 8352412: [CRaC] Direct mapping default changed

[Timofei Pushkin]

Changes the default value of `crexec`'s `direct_map` option to true to have the old behavior by default.

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Commit messages:
 - Direct map by default

Changes: https://git.openjdk.org/crac/pull/216/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=216&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352412
  Stats: 18 lines in 1 file changed: 6 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/crac/pull/216.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/216/head:pull/216

PR: https://git.openjdk.org/crac/pull/216