[tests] Fix test warnings

[honzasterba]

Return in block returns from the parent method, hence some tests did not finish run at all and no-assert-in-test warning was produced.

Motivation and Context

Tests should not generate warning.

How Has This Been Tested?

Only affects tests, the suite passes.

Breaking Changes

None

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Chore - cleanup

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[koic]

Thanks!