[FLINK-35490] Migrate tests to JUnit 5 and AssertJ #690

Job	Run time
License Check	4m 10s
Migration Tests / migration_test_ut (8, 1.19.2)	5m 0s
Migration Tests / migration_test_ut (8, 1.20.1)	5m 23s
Migration Tests / data_stream_migration_test (8, 1.19.2)	9m 58s
Migration Tests / data_stream_migration_test (8, 1.20.1)	10m 0s
Migration Tests / pipeline_migration_test (8, 1.19.2)	9m 35s
Migration Tests / pipeline_migration_test (8, 1.20.1)	8m 25s
Source E2E Tests / compile_and_test (8, 1.19.2)	25m 56s
Source E2E Tests / compile_and_test (8, 1.20.1)	26m 26s
Pipeline E2E Tests (1-Parallelism) / compile_and_test (8, 1.19.2)	36m 31s
Pipeline E2E Tests (4-Parallelism) / compile_and_test (8, 1.19.2)	34m 11s
Pipeline E2E Tests (1-Parallelism) / compile_and_test (8, 1.20.1)	37m 8s
Pipeline E2E Tests (4-Parallelism) / compile_and_test (8, 1.20.1)	36m 20s
Unit Tests (core) / compile_and_test (8, generic)	9m 3s
Unit Tests (db2) / compile_and_test (8, generic)	22m 9s
Unit Tests (mongodb6) / compile_and_test (8, generic)	23m 31s
Unit Tests (mongodb7) / compile_and_test (8, generic)	23m 10s
Unit Tests (mysql) / compile_and_test (8, generic)	45m 32s
Unit Tests (oceanbase) / compile_and_test (8, generic)	6m 31s
Unit Tests (oracle) / compile_and_test (8, generic)	30m 4s
Unit Tests (pipeline_connectors) / compile_and_test (8, generic)	23m 47s
Unit Tests (postgres) / compile_and_test (8, generic)	32m 10s
Unit Tests (sqlserver) / compile_and_test (8, generic)	14m 23s
Unit Tests (tidb) / compile_and_test (8, generic)	3m 26s
Unit Tests (vitess) / compile_and_test (8, generic)	3m 31s
	8h 6m 20s

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