RFR: 8367339: Parallel: Remove PSScavenge::should_scavenge

[Albert Mingkun Yang]

Removing (inlining) a compound method that performs two independent things, loading the obj from a location and checking whether the object belongs to young-gen. Existing callers are changed to use more fine-grained methods, which are more transparent and readable in their context.

Test: tier1-3

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Commit messages:
 - pgc-remove-should-scavenge

Changes: https://git.openjdk.org/jdk/pull/27193/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27193&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367339
  Stats: 104 lines in 8 files changed: 4 ins; 91 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/27193.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27193/head:pull/27193

PR: https://git.openjdk.org/jdk/pull/27193