Fix addMarker in api tests
Fix addMarker in api tests

Tyriar/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js