tests: xfail two shader load tests on Windows

tests/gobj/test_shader.py

@@ -1,6 +1,7 @@
 from panda3d.core import Shader, VirtualFileSystem, Filename
 import time
 import pytest
+import sys
 
 
 @pytest.fixture(scope="session")
@@ -22,6 +23,7 @@ def ramdir():
     vfs.unmount(mount)
 
 
[email protected](sys.platform == "win32", reason="unknown issue")
 def test_shader_load_multi(vfs, ramdir):
     # Try non-existent first.
     shad0 = Shader.load(Shader.SL_GLSL,
@@ -54,6 +56,7 @@ def test_shader_load_multi(vfs, ramdir):
     assert shad2.this != shad1.this
 
 
[email protected](sys.platform == "win32", reason="unknown issue")
 def test_shader_load_compute(vfs, ramdir):
     # Try non-existent first.
     shad0 = Shader.load_compute(Shader.SL_GLSL, "/nonexistent.glsl")