fix: flaky test 09_0036_merge_into_without_dist

[dantengsky]

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Summary

fix flaky test tests/sqllogictests/suites/base/09_fuse_engine/09_0036_merge_into_without_distributed_enable.test, by using different stage names for http/mysql handlers

• fixes: #16456

Tests

• [ ] Unit Test
• [x] Logic Test
• [ ] Benchmark Test
• [ ] No Test - Explain why

Type of change

• [x] Bug Fix (non-breaking change which fixes an issue)
• [ ] New Feature (non-breaking change which adds functionality)
• [ ] Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• [ ] Documentation Update
• [ ] Refactoring
• [ ] Performance Improvement
• [ ] Other (please describe):

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This change is