Disable a new failing test, browser.test_webgl2_ubo_layout_binding. See #13887 (#13987)

Author: kripken

tests/test_browser.py

@@ -1247,6 +1247,7 @@ def test_webgl_explicit_uniform_location(self):
   def test_webgl_sampler_layout_binding(self):
     self.btest('webgl_sampler_layout_binding.c', '1', args=['-s', 'GL_EXPLICIT_UNIFORM_BINDING=1'])
 
+  @unittest.skip('needs to be fixed, see https://github.com/emscripten-core/emscripten/pull/13887#issuecomment-825804449')
   @requires_graphics_hardware
   def test_webgl2_ubo_layout_binding(self):
     self.btest('webgl2_ubo_layout_binding.c', '1', args=['-s', 'GL_EXPLICIT_UNIFORM_BINDING=1', '-s', 'MIN_WEBGL_VERSION=2'])