RFR: 8309538: G1: Move total collection increment from Cleanup to Remark

[Albert Mingkun Yang]

Simple moving `increment_total_collections` to where empty-region reclaim lives.

Test: hotspot_gc

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Commit messages:
 - g1-gc-counter

Changes: https://git.openjdk.org/jdk/pull/14334/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14334&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309538
  Stats: 9 lines in 1 file changed: 5 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14334.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14334/head:pull/14334

PR: https://git.openjdk.org/jdk/pull/14334