TST, BLD: Fix failing aarch64 wheel builds.

The aarch64 wheel build tests are failing with OOM. The new test for
complex128 dot for huge vectors is responsible as the useable memory
is incorrectly determined and the check for sufficient memory fails.
The fix here is to define the `NPY_AVAILABLE_MEM="4 GB"` environment
variable before the test call in `cibw_test_command.sh`.

numpy/core/tests/test_multiarray.py

@@ -6693,7 +6693,7 @@ def assert_dot_close(A, X, desired):
 
     @pytest.mark.slow
     @pytest.mark.parametrize("dtype", [np.float64, np.complex128])
-    @requires_memory(free_bytes=9*10**9)  # complex case needs 8GiB+
+    @requires_memory(free_bytes=18e9)  # complex case needs 18GiB+
     def test_huge_vectordot(self, dtype):
         # Large vector multiplications are chunked with 32bit BLAS
         # Test that the chunking does the right thing, see also gh-22262

tools/wheels/cibw_test_command.sh

@@ -11,7 +11,11 @@ if [[ $RUNNER_OS == "Windows" ]]; then
     PY_DIR=$(python -c "import sys; print(sys.prefix)")
     mkdir $PY_DIR/libs
 fi
-python -c "import sys; import numpy; sys.exit(not numpy.test('full', extra_argv=['-vvv']))"
+
+# Set available memory value to avoid OOM problems on aarch64.
+# See gh-22418.
+export NPY_AVAILABLE_MEM="4 GB"
+python -c "import sys; import numpy; sys.exit(not numpy.test('full'))"
 
 python $PROJECT_DIR/tools/wheels/check_license.py
 if [[ $UNAME == "Linux" || $UNAME == "Darwin" ]] ; then