Remove unused debuggeeCommand function. (#7530)
Remove unused debuggeeCommand function. (#7530)

The function does not seem to be called anywhere,
and make use of target.form, which we want to remove
in Bug 1513565.
ruturajv/debugger.html,bomsy/debugger.html,ruturajv/debugger.html,darkwing/debugger.html,ruturajv/debugger.html,ruturajv/debugger.html,bomsy/debugger.html,devtools-html/debugger.html,devtools-html/debugger.html,darkwing/debugger.html,bomsy/debugger.html,devtools-html/debugger.html,ruturajv/debugger.html,darkwing/debugger.html,darkwing/debugger.html,bomsy/debugger.html,devtools-html/debugger.html,wldcordeiro/debugger.html,ruturajv/debugger.html,darkwing/debugger.html,bomsy/debugger.html,ruturajv/debugger.html,wldcordeiro/debugger.html,devtools-html/debugger.html,darkwing/debugger.html,darkwing/debugger.html,devtools-html/debugger.html,bomsy/debugger.html,wldcordeiro/debugger.html,wldcordeiro/debugger.html,wldcordeiro/debugger.html,bomsy/debugger.html,devtools-html/debugger.html,wldcordeiro/debugger.html,wldcordeiro/debugger.html