ci: drop `-U_FORTIFY_SOURCE` from TSAN job

Coverage report

c57ef54 - 17 hours ago (FAILED)

Base master commit 7988380 used for coverage and benchmarks

Failed to generate report: Essential container in task exited

Pull request run

Report ID 5689

Commit c57ef546c3915e110c3b3cd3aee317e7cb48ee82

Step Functions execution ARN arn:aws:states:ap-south-1:338220712891:execution:start-jobs-default:ac1f8587-4adf-4c5a-b523-ce98c5cf8d2d

Coverage batch job ID Not available

Base master run

Report ID 5651

Commit 7988380da987c0b860885853ace8149b84ac2ee8

Step Functions execution ARN arn:aws:states:ap-south-1:338220712891:execution:start-jobs-default:19a646d5-f552-4aaa-9a46-3ee615444d48

Coverage batch job ID 98da2360-6f52-497e-99ee-422507f6a37b