* alloc.c (Fgarbage_collect): Unblock input after clearing

* alloc.c (Fgarbage_collect): Unblock input after clearing
gc_in_progress to avoid note_mouse_highlight glitch with GC.
* frame.h (FRAME_MOUSE_UPDATE): New macro.
* msdos.c (IT_frame_up_to_date): Use it here...
* w32term.c (w32_frame_up_to_date): ...here...
* xterm.c (XTframe_up_to_date): ...and here...
* nsterm.m (ns_frame_up_to_date): ...but not here.
* lisp.h (Mouse_HLInfo): Remove mouse_face_deferred_gc member.
Adjust users.
* xdisp.c (message2_nolog, message3_nolog, note_mouse_highlight):
Do not check whether GC is in progress.