RFR: 8267612: Declare package-private VarHandle.AccessMode/-Type counts

Slightly reduce VarHandle startup overhead by introducing package-private COUNT constants for two enums ------------- Commit messages: - Declare package-private VarHandle.AccessMode/-Type counts Changes: https://git.openjdk.java.net/jdk/pull/4164/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4164&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8267612 Stats: 18 lines in 4 files changed: 8 ins; 2 del; 8 mod Patch: https://git.openjdk.java.net/jdk/pull/4164.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/4164/head:pull/4164 PR: https://git.openjdk.java.net/jdk/pull/4164