[Spark 4.2 UT] Umbrella: re-enable disabled Spark 4.2 unit tests (GLUTEN-12569)

[akshaytayal]

Umbrella tracking issue for re-enabling the Spark 4.2 unit tests that are currently disabled to keep the gluten-ut/spark42 CI green.

Added in PR #13163 (GLUTEN-12569). 150 UTs are disabled across 7 root-cause themes. Each theme has its own sub-issue with the exact disabled tests, the disable mechanism, and the files updated. As the underlying Gluten/Velox support lands, remove the corresponding .exclude(...) / allowlist / @Ignore / ignore(...) entries and close the sub-issue.

Sub-issues (7)

• [Spark 4.2 UT] Spark 4.2 Storage-Partitioned Join (SPJ) support in Gluten #13174 — Spark 4.2 Storage-Partitioned Join (SPJ) support in Gluten (29 tests)
• [Spark 4.2 UT] Spark 4.2 DSv2 row-level writes (DELETE/MERGE/UPDATE/INSERT) on Gluten path #13175 — Spark 4.2 DSv2 row-level writes (DELETE/MERGE/UPDATE/INSERT) on Gluten path (39 tests)
• [Spark 4.2 UT] Floating-point collection semantics: -0.0/NaN normalization & RESPECT NULLS #13176 — Floating-point collection semantics: -0.0/NaN normalization & RESPECT NULLS (12 tests)
• [Spark 4.2 UT] Golden-file drift on Spark 4.2 (TPC-DS plan-stability + SQLQueryTest .sql) #13177 — Golden-file drift on Spark 4.2 (TPC-DS plan-stability + SQLQueryTest .sql) (46 tests)
• [Spark 4.2 UT] Velox expression & operator gaps (math/TIME/date/broadcast/hash-agg) #13178 — Velox expression & operator gaps (math/TIME/date/broadcast/hash-agg) (6 tests)
• [Spark 4.2 UT] Spark 4.2 framework/API changes breaking Gluten tests (non-velox) #13179 — Spark 4.2 framework/API changes breaking Gluten tests (non-velox) (7 tests)
• [Spark 4.2 UT] File-source & Hive scan (Parquet/ORC ignoreMissingFiles/NullType, bucketed-scan AE, ADD JAR) #13180 — File-source & Hive scan (Parquet/ORC ignoreMissingFiles/NullType, bucketed-scan AE, ADD JAR) (11 tests)

Summary

#	Theme	Items	Sub-issue
1	Spark 4.2 Storage-Partitioned Join (SPJ) support in Gluten	29	#13174
2	Spark 4.2 DSv2 row-level writes (DELETE/MERGE/UPDATE/INSERT) on Gluten path	39	#13175
3	Floating-point collection semantics: -0.0/NaN normalization & RESPECT NULLS	12	#13176
4	Golden-file drift on Spark 4.2 (TPC-DS plan-stability + SQLQueryTest .sql)	46	#13177
5	Velox expression & operator gaps (math/TIME/date/broadcast/hash-agg)	6	#13178
6	Spark 4.2 framework/API changes breaking Gluten tests (non-velox)	7	#13179
7	File-source & Hive scan (Parquet/ORC ignoreMissingFiles/NullType, bucketed-scan AE, ADD JAR)	11	#13180
	Total	150

How these were disabled

• .exclude(...) in gluten-ut/spark42/.../velox/VeloxTestSettings.scala (most suites, honoring BackendTestSettings.shouldRun)
• allowlist removal in gluten-ut/spark42/.../velox/VeloxSQLQueryTestSettings.scala (GlutenSQLQueryTestSuite .sql golden tests — that suite ignores the exclude registry)
• class-level @org.scalatest.Ignore for whole-suite aborts (GlutenBloomFilterFallbackSuite, MiscOperatorSuite, GlutenWholeStageCodegenSuite)
• test(...)->ignore(...) for one standalone test (GlutenAutoAdjustStageResourceProfileSuite)

All disables are CI-confirmed (local-only false-positives were removed via a validation run with excludes reverted).

Related: PR #13163, GLUTEN-12569.