Remove unused find_cudnn_supported_cuda_versions (microsoft#21620)

### Description

The function find_cudnn_supported_cuda_versions is not used anymore.
Remove it.

### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->

onnxruntime/python/onnxruntime_collect_build_info.py

@@ -45,59 +45,3 @@ def get_cudart_version(find_cudart_version=None):
 
     # convert to list and remove None
     return [ver for ver in cudart_found_versions if ver]
-
-
-def find_cudnn_supported_cuda_versions(build_env=False):
-    # comments in get_cudart_version apply here
-    if not sys.platform.startswith("linux"):
-        warnings.warn("find_cudnn_versions only works on Linux")
-
-    cudnn_possible_versions = {None}
-    if not build_env:
-        # if not in a build environment, there may be more than one installed cudnn.
-        # https://developer.nvidia.com/rdp/cudnn-archive to include all that may support Cuda 10+.
-        cudnn_possible_versions.update(
-            {
-                "8.2",
-                "8.1.1",
-                "8.1.0",
-                "8.0.5",
-                "8.0.4",
-                "8.0.3",
-                "8.0.2",
-                "8.0.1",
-                "7.6.5",
-                "7.6.4",
-                "7.6.3",
-                "7.6.2",
-                "7.6.1",
-                "7.6.0",
-                "7.5.1",
-                "7.5.0",
-                "7.4.2",
-                "7.4.1",
-                "7.3.1",
-                "7.3.0",
-            }
-        )
-
-    def get_cudnn_supported_cuda_version(find_cudnn_version=None):
-        cudnn_lib_filename = "libcudnn.so"
-        if find_cudnn_version:
-            cudnn_lib_filename = cudnn_lib_filename + "." + find_cudnn_version
-
-        # in cudnn.h cudnn version are calculated as:
-        # #define CUDNN_VERSION (CUDNN_MAJOR * 1000 + CUDNN_MINOR * 100 + CUDNN_PATCHLEVEL)
-        try:
-            cudnn = ctypes.CDLL(cudnn_lib_filename)
-            # cudnn_ver = cudnn.cudnnGetVersion()
-            cuda_ver = cudnn.cudnnGetCudartVersion()
-            return cuda_ver
-        except Exception:
-            return None
-
-    # use set to avoid duplications
-    cuda_found_versions = {get_cudnn_supported_cuda_version(cudnn_version) for cudnn_version in cudnn_possible_versions}
-
-    # convert to list and remove None
-    return [ver for ver in cuda_found_versions if ver]