fix nodejs tests by bypassing animation loop in headless environments
fix nodejs tests by bypassing animation loop in headless environments

soomin-maeng/cytoscape.js,KonstantinShemyak/cytoscape.js,rlugojr/cytoscape.js,KonstantinShemyak/cytoscape.js,rlugojr/cytoscape.js,soomin-maeng/cytoscape.js