[ROCm] Add thread safety test for hipblaslt GetAlgorithms

[i-chaochen]

Add unit tests to detect potential data races in hipblaslt's MasterSolutionLibrary and ContractionSolution when multiple threads concurrently call GetAlgorithms.

Motivation

This test is designed to help catch race conditions that can cause segfaults in multi-threaded JAX workloads using BF16 GEMM operations, where:

• One thread loads solution libraries (loadLibrary)
• Another thread calls getSolutionByIndex concurrently
• Mutable state like autoGSU is modified without synchronization

Technical Details

The test exercises:

1. Concurrent GetAlgorithms calls on the same plan
2. Concurrent access with different problem sizes (triggers lazy loading)

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[ROCm] Add multi-stream GEMM execution tests for hipblaslt synchronizer buffer race

Add two new test cases to hip_blas_lt_thread_test.cc to exercise concurrent
GEMM execution paths that may trigger the hipblaslt synchronizer buffer race:

• MultiStreamGemmExecutionRace: Creates multiple streams with a shared BlasLt
  plan and executes concurrent GEMM operations, verifying result correctness.

• FireAndForgetGemmRace: More aggressive test with 8 streams and rapid GEMM
  launches to maximize GPU kernel overlap.

These tests allocate device memory, execute actual hipblasLtMatmul operations
via XLA's BlasLt interface, and verify output correctness. While they may not
reliably reproduce the GSU synchronizer buffer race, they serve as:

• Stress tests for concurrent GEMM execution
• Regression tests after hipblaslt fixes are applied
• Documentation of the known multi-stream race condition pattern