patch 8.2.5057: using gettimeofday() for timeout is very inefficient

Problem:    Using gettimeofday() for timeout is very inefficient.
Solution:   Set a platform dependent timer. (Paul Ollis, closes #10505)

src/screen.c

@@ -1760,10 +1760,6 @@ start_search_hl(void)
 	end_search_hl();  // just in case it wasn't called before
 	last_pat_prog(&screen_search_hl.rm);
 	screen_search_hl.attr = HL_ATTR(HLF_L);
-# ifdef FEAT_RELTIME
-	// Set the time limit to 'redrawtime'.
-	profile_setlimit(p_rdt, &screen_search_hl.tm);
-# endif
     }
 }
 
@@ -5029,4 +5025,3 @@ set_chars_option(win_T *wp, char_u **varp)
 
     return NULL;	// no error
 }
-