ENH: Add memory leak tests for itk.Image buffer export paths

Verifies that the NDArrayITKBase reference-holding mechanism does not
introduce memory leaks or prevent garbage collection when all Python
references are released.

itkImageMemoryLeakTest.py (24 assertions):

Section 1 - Weak reference GC verification (13 tests):
  - Image GC'd when np.asarray array is deleted [all versions]
  - Image GC'd when __buffer__ memoryview is deleted [all versions]
  - Image GC'd when array_view_from_image view is deleted [all versions]
  - Image GC'd immediately after itk.array_from_image (deep copy) [all]
  - Image GC'd immediately after np.array(copy=True) [all versions]
  - Image GC'd immediately after __array__(copy=True) [all versions]
  - Image GC'd when chained slice chain is fully deleted [all versions]
  - Pipeline output image GC'd after exported array deleted [all versions]

Section 2 - Reference count verification (5 tests):
  - np.asarray increments image refcount [all versions]
  - Second np.asarray adds another reference [all versions]
  - Refcount restored after del arrays [all versions]
  - __buffer__ increments refcount [all versions]
  - Refcount restored after del memoryview [all versions]

Section 3 - RSS memory growth (4 tests):
  - 200x create-export-delete cycle via np.asarray: < 20 MB growth
  - 200x cycle via __buffer__: < 20 MB growth
  - 200x cycle via array_view_from_image: < 20 MB growth
  - 200x cycle via array_from_image (deep copy): < 20 MB growth

Section 4 - Circular reference detection (2 tests):
  - No uncollectable garbage after np.asarray cycle
  - No uncollectable garbage after __buffer__ cycle

Co-Authored-By: Hans J. Johnson <hans-johnson@uiowa.edu>

Author: hjmjohnson

Modules/Core/Common/wrapping/test/CMakeLists.txt

@@ -66,4 +66,9 @@ if(ITK_WRAP_PYTHON)
     COMMAND
       ${CMAKE_CURRENT_SOURCE_DIR}/itkImageLifetimeTest.py
   )
+  itk_python_add_test(
+    NAME itkImageMemoryLeakPythonTest
+    COMMAND
+      ${CMAKE_CURRENT_SOURCE_DIR}/itkImageMemoryLeakTest.py
+  )
 endif()