test: make hivestore result size checks deterministic

[Jack-LuoHongyi]

Summary

• ensure web page fixtures are flushed and visible before running result-size assertions
• add Hive-specific helpers reused by the result-size test suite
• adapt assertResultSize as the Hive-tailored counterpart to DataStoreTestUtil.testResultSize

Root Cause
Result-size checks relied on immediate schema visibility and deterministic iteration. Hive may expose newly written rows with a delay, yielding divergent counts when the generic helper runs without the additional synchronization provided in other deterministic branches.

Fix

• introduce awaitWebPageSchema, populateWebPages, and sortedWebPageUrls so every query operates on a confirmed schema and stable key ordering
• implement assertResultSize by mirroring the core logic of DataStoreTestUtil.testResultSize(...), while adding Hive-specific guarding against duplicate or missing rows
• route the result-size test methods through the new helper, ensuring consistent setup with the existing query-oriented helpers

This change is constrained to test-only sources; production code remains untouched.

Validation

• the focused result-size test suite continues to succeed under repeated runs
• exercising reordered iteration via edu.illinois:nondex-maven-plugin:2.1.7 reports no discrepancies

Additional Notes
assertResultSize preserves the loop structure and expectations from DataStoreTestUtil.testResultSize(...), adding only the visibility waits and set-based checks required for Hive. The helper functions introduced here are consistent with earlier deterministic fixes for the same class.