Use bool for boolean in w32term.c

Use bool for boolean in w32term.c

 src/w32term.c (x_update_window_begin, x_update_window_end)
 (x_update_end, x_after_update_window_line)
 (x_set_glyph_string_gc, x_draw_glyph_string_background)
 (x_draw_glyph_string_foreground)
 (x_draw_composite_glyph_string_foreground)
 (x_draw_glyphless_glyph_string_foreground)
 (x_draw_image_glyph_string, x_draw_glyph_string)
 (x_draw_stretch_glyph_string, note_mouse_movement)
 (w32_mouse_position, x_scroll_bar_report_motion)
 (x_horizontal_scroll_bar_report_motion, w32_read_socket)
 (w32_set_vertical_scroll_bar, w32_set_horizontal_scroll_bar)
 (w32_draw_window_cursor, x_new_font, x_set_offset)
 (x_set_window_size, x_make_frame_invisible, x_iconify_frame): Use
 bool where appropriate.