Update test_multiarray.py to support numpy 2.0+ (pytorch#138461)

Import _core instead of core.

Addresses partially pytorch#137182
Pull Request resolved: pytorch#138461
Approved by: https://github.com/ezyang, https://github.com/albanD

Author: ccoulombe

test/torch_np/numpy_tests/core/test_multiarray.py

@@ -75,7 +75,12 @@
 IS_PYSTON = False
 HAS_REFCOUNT = True
 
-from numpy.core.tests._locales import CommaDecimalPointLocale
+if numpy.__version__ > "2":
+    # numpy 2.0 +, see https://numpy.org/doc/stable/release/2.0.0-notes.html#renamed-numpy-core-to-numpy-core
+    from numpy._core.tests._locales import CommaDecimalPointLocale
+else:
+    from numpy.core.tests._locales import CommaDecimalPointLocale
+
 from numpy.testing._private.utils import _no_tracing, requires_memory