Fix bug #14558 with turning off mouse-highlight during highlight.

Fix bug #14558 with turning off mouse-highlight during highlight.

 src/xdisp.c (handle_tool_bar_click): When mouse-highlight is off,
 don't insist on being invoked on a highlighted tool-bar button.
 Avoids losing tool-bar functionality when mouse-highlight is nil.
 (note_tool_bar_highlight, note_mode_line_or_margin_highlight):
 Don't highlight when mouse-highlight is nil.
 (note_mouse_highlight): When mouse-highlight is nil, don't return
 right away; instead, run tool-bar and mode-line highlight
 subroutine, clear any existing highlight, and revert the mouse
 pointer to its default shape.