fix callstack release with overload

ml = mlist(["test", "field"], 1);
function out = %test_e(varargin)
    pause
endfunction
function test(ml)
    ml(1);
    [a,b]=where()
    disp(a,b)
endfunction
test(ml);

After using abort, the call stack was not well cleared. So, the next error at the prompt (ie: 1/"e") will show the nonremoved element of the call stack.

After dbe34d30, the ConfigVariable::macroFirstLine_end(); must be done in the pause function instead of in the returnExp.