[rocm-libraries] ROCm/rocm-libraries#6303 (commit 784c268)

CK: Remove 4 orphaned files with verified replacements (~1,025 lines) (#6303)

Depends on #6302

## Summary

Remove 4 orphaned files that have verified replacements already in the
build.

| File | Reason | Replacement |
|------|--------|-------------|
| `test_gemm_pipeline_compiler.cpp` | Refactored into 13 smaller tests |
`_compv3`, `_compv4`, `_mem`, `_persistent`, etc. |
| `test_grouped_gemm_quant.cpp` | Refactored into 5 smaller tests |
`_rowcol`, `_tensor`, `_aquant`, `_bquant`, etc. |
| `..._f8_f8_f16_..._comp_default_instance.cpp` | Superseded by split
files | `_part1.cpp` + `_part2.cpp` |
| `..._f8_f8_f16_..._comp_kpadding_instance.cpp` | Superseded by split
files | `_part1.cpp` + `_part2.cpp` |

Each deletion was verified:
- Original file is NOT in any CMakeLists.txt
- Replacement files ARE in CMakeLists.txt and actively compiled
- Content is fully covered by the replacement files