remove unneeded -O2 in test

tests/runner.py

@@ -7687,7 +7687,7 @@ elif 'browser' in str(sys.argv):
       # SDL, OpenGL, textures, fog, immediate mode. Closure for more coverage
       shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'screenshot.png'))
       self.reftest(path_from_root('tests', 'screenshot-fog-negative.png'))
-      Popen(['python', EMCC, path_from_root('tests', 'sdl_fog_negative.c'), '-O2', '--minify', '0', '-o', 'something.html', '--pre-js', 'reftest.js', '--preload-file', 'screenshot.png']).communicate()
+      Popen(['python', EMCC, path_from_root('tests', 'sdl_fog_negative.c'), '-o', 'something.html', '--pre-js', 'reftest.js', '--preload-file', 'screenshot.png']).communicate()
       self.run_browser('something.html', 'You should see an image with fog.', '/report_result?0')
 
     def test_sdl_fog_density(self):