TST: update xfails for complex special cases

Author: ev-br

array-api-tests-xfails.txt

@@ -29,3 +29,19 @@ array_api_tests/test_statistical_functions.py::test_sum
 
 array_api_tests/test_special_cases.py::test_nan_propagation[cumulative_prod]
 
+# complex special cases which failed "forever"
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is +infinity and imag(x_i) is +0) -> +infinity + 0j]
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is -infinity and imag(x_i) is +infinity) -> -1 + 0j]
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is +infinity and imag(x_i) is +infinity) -> infinity + NaN j]
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is -infinity and imag(x_i) is NaN) -> -1 + 0j]
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is +infinity and imag(x_i) is NaN) -> infinity + NaN j]
+array_api_tests/test_special_cases.py::test_unary[expm1(real(x_i) is NaN and imag(x_i) is +0) -> NaN + 0j]
+array_api_tests/test_special_cases.py::test_unary[expm1((real(x_i) is +0 or real(x_i) == -0) and imag(x_i) is +0) -> 0 + 0j]
+
+array_api_tests/test_special_cases.py::test_unary[sign((real(x_i) is -0 or real(x_i) == +0) and (imag(x_i) is -0 or imag(x_i) == +0)) -> 0 + 0j]
+array_api_tests/test_special_cases.py::test_unary[tanh(real(x_i) is +infinity and isfinite(imag(x_i)) and imag(x_i) > 0) -> 1 + 0j]
+
+# this acosh failure is only seen with python==3.10 and numpy==2.2.6, and not e.g. python 3.12 & numpy 2.4.1
+array_api_tests/test_special_cases.py::test_unary[acosh(real(x_i) is +0 and imag(x_i) is NaN) -> NaN \xb1 \u03c0j/2]
+
+array_api_tests/test_special_cases.py::test_unary[sqrt(real(x_i) is +infinity and isfinite(imag(x_i)) and imag(x_i) > 0) -> +0 + infinity j]