RFR: 8299030: Refactor ReservedSpace::reserve

Mon Dec 19 14:14:34 UTC 2022

Simple refactoring and removing some unnecessary operations.

Test: hotspot_gc

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Commit messages:
 - virtual-refactor

Changes: https://git.openjdk.org/jdk/pull/11723/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11723&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299030
  Stats: 24 lines in 1 file changed: 6 ins; 8 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/11723.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11723/head:pull/11723

PR: https://git.openjdk.org/jdk/pull/11723