Tests how utilities functions highlight text and then revert/re-apply highlighting changes.

Bug 70244
--------- Running test: ----------
After highlight: [function]
After revert: function
After apply: [function]
--------- Running test: ----------
After highlight: [functio]n
After revert: function
After apply: [functio]n
--------- Running test: ----------
After highlight: f[unction]
After revert: function
After apply: f[unction]
--------- Running test: ----------
After highlight: f[unctio]n
After revert: function
After apply: f[unctio]n
--------- Running test: ----------
After highlight: [function functionName]
After revert: function functionName
After apply: [function functionName]
--------- Running test: ----------
After highlight: [function functionNam]e
After revert: function functionName
After apply: [function functionNam]e
--------- Running test: ----------
After highlight: f[unction functionName]
After revert: function functionName
After apply: f[unction functionName]
--------- Running test: ----------
After highlight: f[unction functionNam]e
After revert: function functionName
After apply: f[unction functionNam]e
--------- Running test: ----------
After highlight: functio[n f]unctionName
After revert: function functionName
After apply: functio[n f]unctionName
--------- Running test: ----------
After highlight: [f]unction[ ][f]unctionName
After revert: function functionName
After apply: [f]unction[ ][f]unctionName
--------- Running test: ----------
After highlight: functio[n][ ]functionNam[e]
After revert: function functionName
After apply: functio[n][ ]functionNam[e]
--------- Running test: ----------
After highlight: [f]unctio[n f]unctionNam[e]
After revert: function functionName
After apply: [f]unctio[n f]unctionNam[e]