RFR: 8283456: Make CompiledICHolder::live_count/live_not_claimed_count debug only

[Zhengyu Gu]

Please review this trivial patch to make `CompiledICHolder::live_count/live_not_claimed_count` debug only, since they are only updated/used in debug only code.

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

Commit messages:
 - 8283456: Make CompiledICHolder::live_count/live_not_claimed_count debug only

Changes: https://git.openjdk.java.net/jdk/pull/7890/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7890&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283456
  Stats: 8 lines in 2 files changed: 5 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7890.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7890/head:pull/7890

PR: https://git.openjdk.java.net/jdk/pull/7890