Fix pipe tablet memory self-lock during batching

[Caideyipi]

Description

Problem

A realtime Pipe with pattern.exclusion can convert InsertNode events into retained raw tablet events. These events create zero-sized PipeTabletMemoryBlocks and account for their memory later through forceResize.

Before this change, forceResize checked only the remaining non-floating memory. It did not apply the tablet/TsFile admission thresholds used by non-zero initial allocations. Raw tablets could therefore fill the whole non-floating pool. Once full, the sink batch could not allocate even the small buffer needed to transfer and release those tablets, causing a memory self-lock and a frozen RemainingEventCount.

Fix

Apply the existing tablet/TsFile hard admission thresholds when a typed data-structure block grows through resize. Normal blocks, including sink batch buffers, retain the existing total-memory check.

This backpressures raw-tablet production before it exhausts the pool and leaves memory for downstream transfer and release. It also avoids restoring a full static reservation for every sink batch.

A package-private constructor accepting IMemoryBlock was added so the memory policy can be tested with a deterministic, isolated memory pool.

Tests

Added PipeMemoryManagerResizeTest to verify that:

• tablet growth is rejected after the tablet threshold is reached;
• a normal sink batch can still allocate memory;
• tablet growth resumes after retained tablet memory is released;
• all accounted memory returns to zero.

Executed:

mvn -Ddevelocity.off=true -o test -pl iotdb-core/datanode -Dtest=PipeMemoryManagerResizeTest,PipeTabletEventPlainBatchTest,TsFileInsertionEventParserTest

Result: 25 tests run, 0 failures, 0 errors, 3 skipped.

---

This PR has:

• been self-reviewed.
  • concurrent read
  • concurrent write
• added comments explaining the why and the intent of the code wherever it would not be obvious.
• added unit tests to cover the new code path.

---

Key changed/added classes in this PR

• PipeMemoryManager
• PipeMemoryManagerResizeTest