HBASE-30394 Report data block size and count separately in TinyLfuBlockCache

[Huginn-kio]

HBASE-30394

Summary

TinyLfuBlockCache currently exposes aggregate cache size and entry count through
the data-block-specific BlockCache methods. This PR tracks data-block size and
count separately.

See HBASE-30394.

Root cause

getCurrentDataSize() delegates to getCurrentSize() and
getDataBlockCount() delegates to getBlockCount(). Insert and removal paths
do not maintain data-only counters, so index and metadata blocks are included.

Fix

• Track aligned heap size and count for blocks whose BlockType is data.
• Update both counters on cache insertion, explicit eviction, and listener eviction.
• Return the data-only counters from the existing BlockCache methods.

Testing

• git diff --check
• JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home mvn -pl hbase-server -am -DskipTests checkstyle:check -Dcheckstyle.includes='**/io/hfile/TinyLfuBlockCache.java'
• JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home mvn -pl hbase-server -am -DskipTests -Dcheckstyle.skip -Drat.skip -Dspotbugs.skip compile
• No new regression test was added; this PR contains the focused implementation fix.

Compatibility

• Public API impact: none; this uses existing BlockCache methods.
• Config impact: none.
• Persisted and wire format impact: none.