Revert "[common] Add support for cuBLASLt GEMM for GroupedTensor (#2502)"

This reverts commit 9bb9d22.

Author: KshitijLakhani

tests/cpp/operator/CMakeLists.txt

@@ -30,7 +30,6 @@ add_executable(test_operator
                test_causal_softmax.cu
                test_swizzle.cu
                test_swap_first_dims.cu
-               test_grouped_gemm.cu
                ../test_common.cu)
 
 # Find required packages