Fix ID collision in MetaDataInstanceFactory for test scenarios with @SpringBatchTest

[HongYeseul]

Problem

Tests using StepScopeTestUtils with @SpringBatchTest failed with ClassCastException due to ID collisions. MetaDataInstanceFactory always created instances with the same default IDs (123L), causing multiple StepExecution instances to be treated as identical in StepSynchronizationManager.

Solution

Added AtomicLong counters to generate unique IDs for each StepExecution and JobExecution. This prevents context collisions while maintaining backward compatibility—the first invocation still uses the original default IDs.

Changes

• Added jobExecutionIdCounter and stepExecutionIdCounter static fields
• Updated createStepExecution(JobParameters) to use incrementAndGet() for unique IDs
• Added test case to verify unique ID generation

Closes #5181