Restore XFLOATINT but with restricted args

Restore XFLOATINT but with restricted args

Turn instances of extract_float into XFLOAT_DATA when possible,
and to a resurrected XFLOATINT when the arg is a number.
The resurrected XFLOATINT is more like XFLOAT and XINT in
that is valid only if its arg is a number.  This clarifies
the ways in which floats can be extracted at the C level.
* src/editfns.c (styled_format):
* src/floatfns.c (extract_float, Fexpt):
Use XFLOATINT rather than open-coding it.
* src/fns.c (internal_equal):
* src/image.c (imagemagick_load_image):
* src/xdisp.c (resize_mini_window):
Prefer XFLOAT_DATA to extract_float on values known to be floats.
* src/frame.c (x_set_screen_gamma):
* src/frame.h (NUMVAL):
* src/image.c (x_edge_detection, compute_image_size):
* src/lread.c (read_filtered_event):
* src/window.c (Fset_window_vscroll):
* src/xdisp.c (handle_single_display_spec, try_scrolling)
(redisplay_window, calc_pixel_width_or_height, x_produce_glyphs)
(on_hot_spot_p):
Prefer XFLOATINT to extract_float on values known to be numbers.
* src/lisp.h (XFLOATINT): Bring back this function, except
it now assumes its argument is a number.