[fix](clucene) Support block WAND in composite readers

[hoshinojyunn]

What problem does this PR solve?

Issue Number: close #62955

Related PR: None

Problem Summary:

The fix/multi-reader-block-wand branch adds block-WAND support for composite
readers (MultiReader / MultiTermDocs). The block APIs previously worked only
for a segment reader, so a caller using a composite reader could not read block
postings or use block-level statistics.

This change:

• Implements readBlock, skipToBlock, getMaxBlockFreq, getMaxBlockNorm,
  and getLastDocInBlock in MultiTermDocs.

• Converts child-reader-local doc IDs and block boundaries into global doc IDs,
  while preserving each physical block, including a short tail block, rather
  than merging blocks across child-reader boundaries.

• Reports a reader transition from skipToBlock even when the destination
  child has fewer postings than the skip interval and therefore cannot perform
  a local skip. This invalidates the block-WAND caller's cached block metadata.

• Fixes the SegmentTermDocs::skipToBlock posting count after a skip-list
  lookup in the first physical block:

  count = newCount < 0 ? 0 : newCount;

  DefaultSkipListReader::skipTo() returns -1 when no skip entry precedes
  the target, which means the target is in the first physical block and the
  frequency stream is positioned at its beginning. At that point no posting
  has been consumed, so count must be 0, not -1.

  For example, consider 1,149 postings stored as blocks of 511, 512, and 126
  postings. A skipToBlock() target in the first block returns newCount == -1. If count remains -1, the subsequent block reads make it 510, 1,022,
  and 1,148, respectively. The reader then believes one posting remains after
  the 126-posting tail and tries to read beyond the physical postings. Starting
  from count = 0 instead yields 511, 1,023, and 1,149, so iteration stops at
  the correct boundary.

Regression coverage in TestReadRange.cpp verifies:

• Composite readBlock() output, global doc IDs, and block metadata against
  next() for two readers with 1,149 and 1,134 documents, including expected
  511/512/tail physical block layouts.
• skipToBlock() before and across reader boundaries, including a target in a
  short tail block.
• Reader transitions into a child with only 11 postings, both from a short
  first reader and after a block skip in a larger first reader.

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test: be/ut_build_ASAN/bin/cl_test testReadRange
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes. Composite readers now expose block-WAND APIs and report
    cross-reader block state transitions.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label