Avoid testing using platform on windows

Author: avmarchenko

appveyor.yml

@@ -50,7 +50,6 @@ install:
           {$root = "C:\Miniconda-x64"}
         $env:path="$root;$root\Scripts;$root\Library\bin;$($env:path)"
 
-  - cmd: setx NUMBA_DISABLE_JIT "1"
   - cmd: conda config --set show_channel_urls true
   - cmd: conda config --set always_yes yes --set changeps1 no
   - cmd: conda update -n base conda

exa/util/tests/test_nbvars.py

@@ -9,13 +9,14 @@
 """
 import os
 import pytest
+import platform
 import numpy as np
 import sympy as sy
 from numba.errors import TypingError
 from exa.util.nbvars import numbafy
 
 
-NUMBA_DISABLE_JIT = os.environ.get("NUMBA_DISABLE_JIT", 0) == 1
+NUMBA_DISABLE_JIT = os.environ.get("NUMBA_DISABLE_JIT", 0) == 1 or platform.system() == "Windows"
 
 
 @pytest.fixture