MDL-46891 behat: Create new table node, don't set values again.
MDL-46891 behat: Optimised login step and context helper
MDL-46891 behat: selenium2Driver expects JS to be in 1 line

MinkSelenium2Driver #112 introduced check for JS
to be 1 line and prefix return if first word is
not return, so modifyed JS to respect this