Test shared memory cache with reduced size

It looks like the RAPIDS CI/CD is launching the docker container with a reduced shared memory size. This is causing the shared memory cache to be failed with
'RuntimeError: No space left on device'.

Signed-off-by: Gigon Bae <gbae@nvidia.com>

python/cucim/tests/unit/clara/test_image_cache.py

@@ -68,24 +68,24 @@ def test_get_per_process_cache():
 def test_get_shared_memory_cache():
     from cucim import CuImage
 
-    cache = CuImage.cache("shared_memory", memory_capacity=128)
+    cache = CuImage.cache("shared_memory", memory_capacity=32)
     assert int(cache.type) == 2
     assert cache.memory_size == 0
     # It allocates additional memory
-    assert cache.memory_capacity > 2**20 * 128
-    assert cache.free_memory > 2**20 * 128
+    assert cache.memory_capacity > 2**20 * 32
+    assert cache.free_memory > 2**20 * 32
     assert cache.size == 0
     assert cache.capacity > 0
     assert cache.hit_count == 0
     assert cache.miss_count == 0
 
     config = cache.config
     # Check essential properties
-    #  {'type': 'shared_memory', 'memory_capacity': 2048, 'capacity': 682,
+    #  {'type': 'shared_memory', 'memory_capacity': 32, 'capacity': 170,
     #   'mutex_pool_capacity': 100003, 'list_padding': 10000,
     #   'extra_shared_memory_size': 100, 'record_stat': False}
     assert config["type"] == "shared_memory"
-    assert config["memory_capacity"] == 128
+    assert config["memory_capacity"] == 32
     assert not config["record_stat"]