RFR: 8314651: G1: Fix -Wconversion warnings in static fields of HeapRegion

Mon Aug 21 12:32:35 UTC 2023

Use unsigned type for heap-region-size related shifts in HeapRegion.

Test: tier1-3

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Commit messages:
 - g1-heap-region-log-uint

Changes: https://git.openjdk.org/jdk/pull/15360/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15360&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314651
  Stats: 22 lines in 8 files changed: 2 ins; 4 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/15360.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15360/head:pull/15360

PR: https://git.openjdk.org/jdk/pull/15360