RFR: 8296374: Check for young region in G1BarrierSet::invalidate instead of card-by-card check [v2]

[Ivan Walulya]

> Hi,
> 
> Please review this change to young region card checks in G1BarrierSet::invalidate(). A single check should suffice because the MemRegion for invalidation in G1 is either completely in the young gen or not. 
> 
> Testing: Tier 1-3

Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:

  Albert review

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/11677/files
  - new: https://git.openjdk.org/jdk/pull/11677/files/3039f5e4..58bf53a8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11677&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11677&range=00-01

  Stats: 15 lines in 1 file changed: 0 ins; 2 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/11677.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11677/head:pull/11677

PR: https://git.openjdk.org/jdk/pull/11677